---------------------------------------------------------- Kolb-List Digest Archive --- Total Messages Posted Thu 07/05/18: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:23 AM - Re: Firestar/HKS Engine Test Run (Bill Berle) 2. 06:01 AM - Re: Firestar/HKS Engine Test Run (Gary Aman) 3. 06:22 AM - Re: Firestar/HKS Engine Test Run (Charlie England) 4. 08:40 AM - Re: Firestar/HKS Engine Test Run (John Hauck) 5. 08:44 AM - Re: Firestar/HKS Engine Test Run (John Hauck) 6. 08:44 AM - Re: Firestar/HKS Engine Test Run (John Hauck) 7. 10:02 AM - Re: Firestar/HKS Engine Test Run (Charlie England) ________________________________ Message 1 _____________________________________ Time: 01:23:57 AM PST US From: Bill Berle Subject: Re: Kolb-List: Firestar/HKS Engine Test Run Thank you guys again for putting your brains on this :) A year ago I had contacted Jerry Olenik at Green Sky (RIP Jerry), and he gave me a rough number of "something about 24 inches" between the exhaust flange and the merge. That is what we built. I had actually sent HKS Japan an e-mail and got no reply whatsoever (not even a rejection to my request for info). That was disappointing, and not 100% professional on their part. The exhaust has a "restraining collar" bolted to the bolt that holds the tailboom tube to the fuselage at the back of the cage. This restraint is like a giant Adel clamp, except it has 1/8" gap around the exhaust pipe. The concept (per my aero engineer) is to prevent the exhaust from moving much or get into the prop, but to allow it to move a little so it can adjust itself in the muffler due to movement and heat expansion. This restraint is well below the flex joint, but before the pipe bends around the tailboom towards the muffler. I have made arrangements to borrow a prop balancer, to at least eliminate that as the culprit. I'm also going to re-pitch the prop, at the same time as checking the runout. As mentioned, there's no runout adjustment on this prop, so it may be moot. One other possibility for the runout is that as the prop blades pass near the exhaust and the rear of the cage, there is a "dead spot" or eddy current of air that allows that blade to see a little different in-flow or out-flow, resulting in THAT blade making a little less or more thrust at that instant, causing an aerodynamic fore-aft vibration (as opposed to a mass balance problem). Bill Berle www.ezflaphandle.com - safety & performance upgrade for light aircraft www.grantstar.net - winning proposals for non-profit and for-profit entities -------------------------------------------- On Wed, 7/4/18, Richard Girard wrote: Subject: Re: Kolb-List: Firestar/HKS Engine Test Run To: "kolb-list@matronics.com" Date: Wednesday, July 4, 2018, 9:34 PM Bill, I've been flying in front of an HKS on my trike for 11 years. It does not shake as you describe yours. Even when I first flew it with the carbs significantly out of synch it was smooth. The only shaking it does is on shutdown. Since you've already synched the carbs it should run like a sewing machine. Sorry I can't tell you anything more than your engine is not running properly.I looked up the info I got from the HKS group. "Jim Carruthers fabricated the exhaust system for my HKS when he did the install on my Avid. We contacted HKS in Japan about exhaust system requirements and received a reply back from an HKS engineer. He said the headers need to merge at 500mm for proper scavenging and the length after the merge was not critical though he noted that installations with excessively long pipes after the merge had experienced rough idling issues. As far as individual headers with no merge, there was an HKS on a Skyraider at OshKosh years ago that had independent headers going to super trapp mufflers. They had a difficult time getting the engine to run well and it was way off on power. Jim routed my exhaust tubes to merge as close to 500mm as room would allow in the cowling and my engine runs fantastic. Right after the merge he rolled a simple muffler can with no baffles and its pretty quiet." Hope this helps,Rick On Wed, Jul 4, 2018 at 9:43 PM, George Helton wrote: George Helton I put vgs on my Firestar a year ago. I did the bottom of horizontal stabilizers and the wings. They work well. George H. Firestar FS100, Hirth 2702 14GDH Mesick, Michigan gdhelton@gmail.com Sent from my iPhone > On Jul 4, 2018, at 6:34 PM, Bill Berle wrote: > > > Thank you all for your input and opinions... I appreciate it. > > All that brightly colored junk lashed to the boom tube is the big tow strap that we used to tie the airplane to the Jeep. The tow strap looked big enough to lift a Sherman tank ! > > The 4" diameter silver tube under the tailboom is that Swiss Muffler I was talking about. Put it in the "woulda - coulda - shoulda worked" category. Regardless, I do need some sort of muffler, and this one actually works about as good as the stock HKS system, it just doesn't make a "wow!" difference like I thought it would. > > It is the tallest Kolb I've ever seen too... that was the big plan all along, to get the wing angle up high . Nothing was custom-built or scientifically researched about it... it's just a set of taller steel gear legs from the Kolb Slingshot, with 21 inch Desser bush tires. I'm not a tall guy by any means but I can get in and out OK. The trick is backing my butt up to the fuselage side, stepping on the tire, and hoisting myself up onto the side of the cockpit (longeron). It is a little easier than it looks. I WAS wondering if I was going to have to have a one rung rope ladder or step stool or toe strap or something to get in. Turns out I don't need it. > > Using the bottom of the wing as the reference, the airplane sits up at an 18 degree angle of attack (deck angle actually) when on the wheels. It's even a little more when it's on those roller skates that I use to move it in and out of the hangar. > > I will indeed check the propeller runout when I re-pitch it. It may be a moot point, there is apparently no adjustment that I can make to it. I do not believe the crankshaft is bent, and there is no visible damage to the propeller hub. > > In my own defense, the wing pins were only in temporarily, to get the wings out of the way of the propeller. The aircraft was NOT going to fly or even taxi on that day. > > I hope I'm not going to get any one upset or annoyed, but I have purchased a set of vortex generators for it, and those are going on ASAP. The VG's have now been shown to work well on the Kolb wing design, and several of the more experienced Kolbers seem to agree that they work as advertised. Because I have such a high grorund angle on mine, I would guess that my airplane would be even more prone to stalling on landing, doing the "Kolb Quit" maneuver. In order to get a 3 point landing I will probably have to pull the stick farther back than with other Kolbs, and wait a little longer before the tail comes all the way down. Which would put me at greater risk of that stall/drop. So the VG's will hopefully give me a little more margin while I am learning how to fly the airplane. > > Bill Berle > > > ------------------------------ -------------- > On Wed, 7/4/18, Charlie England wrote: > > Subject: Re: Kolb-List: Firestar/HKS Engine Test Run > To: kolb-list@matronics.com > Date: Wednesday, July 4, 2018, 2:42 PM > > Hey Bill, > in that HBA link, you mentioned 1/2" of runout on the > prop. Did you check blade runout prior to engine start? That > much runout by itself could shake the engine off the plane. > A prop is a prop, UL or not, and if it isn't running > true, with exactly the same pitch on all blades, you're > going to get vibration. > Charlie > On Wed, Jul 4, 2018 at 4:15 > PM, George Helton > wrote: > Well > Bill, I guess you should have learned a valuable lesson > about not only Kolbs but any aircraft. If you install a pin, > safety it, period. If you put a bolt in, put nut on it and > safety it. As far as the vibration goes, youve got a wide > range on your idle setting. Dont worry about the rpm so > much as finding at sweet spot where it runs > smoothest. Is all that stuff youve got lashed to > the boom tube the muffler youve been telling us about? > Whew, sometimes our best ideas an efforts just dont seem > to work out. Ive been there before. I think thats the > tallest Kolb Ive ever seen. Im on the short side so > Id need a ladder just to get into the cockpit. Good > luck! George H.Firestar FS100, Hirth > 270214GDH Mesick, > Michigan gdhelton@gmail.com > > Sent > from my iPhone > On Jul 4, 2018, at > 3:03 PM, Rick Neilsen > wrote: > > Bill > I'm sure Larry will chime with > his HKS knowledge. > You need to get over that airplane > vs Ultralight thing. Vibrations are bad news. My redrive VW > runs smoother at cruise RPMs than any GA airplane I have > ever flown. > Most airplane engines have RPMs > that you stay away from or pass through quickly. The HKS is > known for its smoothness. I have to believe that what you > have experienced is torsional resonance. Take the prop off > and it will likely run smooth a silk. The higher the > compression and fewer the cylinders the harder it is to > tame. Geared engines are more prone to this issue but some > direct drive/prop engines have issues also. Internal > combustion engines will slow down on compression stroke and > speed up on ignition stroke. A prop wants to turn a constant > RPM. When a prop is subjected to these drastic changes in > RPM (resonance) the prop blades will whip around and do > nasty things and sometimes worse. All reduction drive > engines have some form of dampening device to reduce this > resonance but will likely not work sufficiently at all RPMs > (normally have more issues at idle RPMs). It is also > possible that engine/prop combination will not > work. > Worth what you paid for > it. > Rick NeilsenRedrive VW Powered > MKIIIC > On Wed, Jul > 4, 2018 at 1:20 PM Bill Berle > wrote: > Greetings > Kolbers, > > > > Yesterday we finally were able to test run the HKS engine > installation on my Firestar 2. The HKS engine started right > up and ran, but it needed carburetor adjustment. I had a > friend there who has experience with the HKS engine, and he > was kind enough to adjust the carburetors using a dual > vacuum gauge. > > > > The one big issue I had was that the engine vibration was > far far more than I was ever used to seeing on an aircraft. > Part of this is that I'm "an airplane guy" > instead of "an ultralight guy", Part of it is that > the HKS is an opposed 2 cylinder engine with a very high > compression ratio (11 to 1). But part of this is also that > it did shake and vibrate a LOT, and I started thinking about > how things tend to get loose and rattle apart in a high > vibration environment. > > > > The one thing that really worried me is that around idle > speed something became resonant and the wing struts started > to vibrate up and down in the middle, maybe half an inch up > and hald an inch down versus a straight line. Aluminum does > NOT like this kind of vibration! Neither do fasteners. After > about two minutes we shut the engine down, and someone foun > the wing strut attachment pin (the short clevis pin) on the > ground next to the airplane. I had put the pin in place from > above without the safety pin )ground runs only). The > vibration backed the pin completely out! > > > > Does anyone else have this kind of wing strut vibration with > the Kolb? > > > > Photos of the test run and adjustment wre posted here, > scroll halfway down the page to to post # 952 > > > > http://www.homebuiltairplanes. > com/forums/showthread.php?t 28504&page=64&p=433039# > post433039 > > > > Bill Berle > > www.ezflaphandle.com > - safety & performance upgrade for light aircraft > > www.grantstar.net > - winning proposals for non-profit and for-profit > entities > > > > > > ==== ============================== = -List" rel="noreferrer" target="_blank">http://www.matronics.com/Navig ator?Kolb-List ==== ============================== = FORUMS - eferrer" target="_blank">http://forums.matronics.com ==== ============================== = WIKI - errer" target="_blank">http://wiki.matronics.com ==== ============================== = b Site - -Matt Dralle, List Admin. rel="noreferrer" target="_blank">http://www.matronics.com/contr ibution ==== ============================== = -- Blessed are the cracked, for they shall let in the light. Groucho Marx ________________________________ Message 2 _____________________________________ Time: 06:01:08 AM PST US From: Gary Aman Subject: Re: Kolb-List: Firestar/HKS Engine Test Run just as an aside on your exhaust system,any exhaust that exits near the tube will travel along it and be drawn into the rear of the tube and blow into the cockpit like someone is back there with a leaf blower.I had to fashion a foam rubber plug to seal off the air flow up the tube, 6=9D thick with slits for the cables.The vg=99s are the way to go, even with my MK3C short spring steel gear legs,the tail wheel touches down first when I=99m solo. G.Aman MK3C Jabiru 2200A 1060hrs > On Jul 5, 2018, at 4:23 AM, Bill Berle wrote: > > > > Thank you guys again for putting your brains on this :) > > A year ago I had contacted Jerry Olenik at Green Sky (RIP Jerry), and he gave me a rough number of "something about 24 inches" between the exhaust flange and the merge. That is what we built. I had actually sent HKS Japan an e-mail and got no reply whatsoever (not even a rejection to my request for info). That was disappointing, and not 100% professional on their part. > > The exhaust has a "restraining collar" bolted to the bolt that holds the tailboom tube to the fuselage at the back of the cage. This restraint is like a giant Adel clamp, except it has 1/8" gap around the exhaust pipe. The concept (per my aero engineer) is to prevent the exhaust from moving much or get into the prop, but to allow it to move a little so it can adjust itself in the muffler due to movement and heat expansion. This restraint is well below the flex joint, but before the pipe bends around the tailboom towards the muffler. > > I have made arrangements to borrow a prop balancer, to at least eliminate that as the culprit. I'm also going to re-pitch the prop, at the same time as checking the runout. As mentioned, there's no runout adjustment on this prop, so it may be moot. > > One other possibility for the runout is that as the prop blades pass near the exhaust and the rear of the cage, there is a "dead spot" or eddy current of air that allows that blade to see a little different in-flow or out-flow, resulting in THAT blade making a little less or more thrust at that instant, causing an aerodynamic fore-aft vibration (as opposed to a mass balance problem). > > > Bill Berle > www.ezflaphandle.com - safety & performance upgrade for light aircraft > www.grantstar.net - winning proposals for non-profit and for-profit entities > > -------------------------------------------- > On Wed, 7/4/18, Richard Girard > wrote: > > Subject: Re: Kolb-List: Firestar/HKS Engine Test Run > To: "kolb-list@matronics.com " > > Date: Wednesday, July 4, 2018, 9:34 PM > > Bill, I've been > flying in front of an HKS on my trike for 11 years. It does > not shake as you describe yours. Even when I first flew it > with the carbs significantly out of synch it was smooth. The > only shaking it does is on shutdown. Since you've > already synched the carbs it should run like a sewing > machine. Sorry I can't tell you anything more than your > engine is not running properly.I looked up the info I > got from the HKS group. > " Jim > Carruthers fabricated the exhaust system for my HKS when he > did the install on my Avid. We contacted HKS in Japan > about exhaust system requirements and received a reply back > from an HKS engineer. He said the headers need to merge at > 500mm for proper scavenging and the length after the > merge was not critical though he noted that installations > with excessively long pipes after the merge had experienced > rough idling issues. As far as individual headers with no > merge, there was an HKS on a Skyraider at OshKosh years ago > that had independent headers going to super trapp mufflers. > They had a difficult time getting the engine to run well and > it was way off on power. Jim routed my exhaust tubes to > merge as close to 500mm as room would allow in the cowling > and my engine runs fantastic. Right after the merge he > rolled a simple muffler can with no baffles and its pretty > quiet." > Hope this > helps,Rick > > > > > > On Wed, Jul 4, 2018 at > 9:43 PM, George Helton > > wrote: > George Helton > > > > > I put vg=99s on my Firestar a year ago. I did the bottom of > horizontal stabilizers and the wings. They work well. > > George H. > > Firestar FS100, Hirth 2702 > > 14GDH > > Mesick, Michigan > > gdhelton@gmail.com > > > > Sent from my iPhone > > > >> On Jul 4, > 2018, at 6:34 PM, Bill Berle > > wrote: > >> > > >> > >> Thank you all for your input and opinions... I > appreciate it. > >> > >> All that brightly colored junk lashed to the boom tube > is the big tow strap that we used to tie the airplane to the > Jeep. The tow strap looked big enough to lift a Sherman tank > ! > >> > >> The 4" diameter silver tube under the tailboom is > that Swiss Muffler I was talking about. Put it in the > "woulda - coulda - shoulda worked" category. > Regardless, I do need some sort of muffler, and this one > actually works about as good as the stock HKS system, it > just doesn't make a "wow!" difference like I > thought it would. > >> > >> It is the tallest Kolb I've ever seen too... that > was the big plan all along, to get the wing angle up high . > Nothing was custom-built or scientifically researched about > it... it's just a set of taller steel gear legs from the > Kolb Slingshot, with 21 inch Desser bush tires. I'm > not a tall guy by any means but I can get in and out OK. The > trick is backing my butt up to the fuselage side, stepping > on the tire, and hoisting myself up onto the side of the > cockpit (longeron). It is a little easier than it looks. I > WAS wondering if I was going to have to have a one rung rope > ladder or step stool or toe strap or something to get in. > Turns out I don't need it. > >> > >> Using the bottom of the wing as the reference, the > airplane sits up at an 18 degree angle of attack (deck angle > actually) when on the wheels. It's even a little more > when it's on those roller skates that I use to move it > in and out of the hangar. > >> > >> I will indeed check the propeller runout when I > re-pitch it. It may be a moot point, there is apparently no > adjustment that I can make to it. I do not believe the > crankshaft is bent, and there is no visible damage to the > propeller hub. > >> > >> In my own defense, the wing pins were only in > temporarily, to get the wings out of the way of the > propeller. The aircraft was NOT going to fly or even taxi on > that day. > >> > >> I hope I'm not going to get any one upset or > annoyed, but I have purchased a set of vortex generators for > it, and those are going on ASAP. The VG's have now > been shown to work well on the Kolb wing design, and several > of the more experienced Kolbers seem to agree that they work > as advertised. Because I have such a high grorund angle on > mine, I would guess that my airplane would be even more > prone to stalling on landing, doing the "Kolb > Quit" maneuver. In order to get a 3 point landing I > will probably have to pull the stick farther back than with > other Kolbs, and wait a little longer before the tail comes > all the way down. Which would put me at greater risk of > that stall/drop. So the VG's will hopefully give me a > little more margin while I am learning how to fly the > airplane. > >> > >> Bill Berle > >> > >> > >> ------------------------------ -------------- > >> On Wed, 7/4/18, Charlie England > wrote: > >> > >> Subject: Re: Kolb-List: Firestar/HKS Engine Test Run > >> To: kolb-list@matronics.com > >> Date: Wednesday, July 4, 2018, 2:42 PM > >> > >> Hey Bill, > >> in that HBA link, you mentioned 1/2" of runout on > the > >> prop. Did you check blade runout prior to engine start? > That > >> much runout by itself could shake the engine off the > plane. > >> A prop is a prop, UL or not, and if it isn't > running > >> true, with exactly the same pitch on all blades, > you're > >> going to get vibration. > >> Charlie > >> On Wed, Jul 4, 2018 at 4:15 > >> PM, George Helton > >> wrote: > >> Well > >> Bill, I guess you should have learned a valuable > lesson > >> about not only Kolbs but any aircraft. If you install a > pin, > >> safety it, period. If you put a bolt in, put nut on it > and > >> safety it. As far as the vibration goes, you=99ve got a > wide > >> range on your idle setting. Don=99t worry about the rpm > so > >> much as finding at sweet spot where it runs > >> smoothest. Is all that stuff you=99ve got lashed to > >> the boom tube the muffler you=99ve been telling us > about? > >> Whew, sometimes our best ideas an efforts just don=99t > seem > >> to work out. I=99ve been there before. I think that=99s > the > >> tallest Kolb I=99ve ever seen. I=99m on the short side > so > >> I=99d need a ladder just to get into the cockpit. Good > >> luck! George H.Firestar FS100, Hirth > >> 270214GDH Mesick, > >> Michigan gdhelton@gmail.com > >> > >> Sent > >> from my iPhone > >> On Jul 4, 2018, at > >> 3:03 PM, Rick Neilsen > >> wrote: > >> > >> Bill > >> I'm sure Larry will chime with > >> his HKS knowledge. > >> You need to get over that airplane > >> vs Ultralight thing. Vibrations are bad news. My > redrive VW > >> runs smoother at cruise RPMs than any GA airplane I > have > >> ever flown. > >> Most airplane engines have RPMs > >> that you stay away from or pass through quickly. The > HKS is > >> known for its smoothness. I have to believe that what > you > >> have experienced is torsional resonance. Take the prop > off > >> and it will likely run smooth a silk. The higher the > >> compression and fewer the cylinders the harder it is > to > >> tame. Geared engines are more prone to this issue but > some > >> direct drive/prop engines have issues also. > Internal > >> combustion engines will slow down on compression stroke > and > >> speed up on ignition stroke. A prop wants to turn a > constant > >> RPM. When a prop is subjected to these drastic changes > in > >> RPM (resonance) the prop blades will whip around and > do > >> nasty things and sometimes worse. All reduction drive > >> engines have some form of dampening device to reduce > this > >> resonance but will likely not work sufficiently at all > RPMs > >> (normally have more issues at idle RPMs). It is also > >> possible that engine/prop combination will not > >> work. > >> Worth what you paid for > >> it. > >> Rick NeilsenRedrive VW Powered > >> MKIIIC > >> On Wed, Jul > >> 4, 2018 at 1:20 PM Bill Berle > >> wrote: > >> Greetings > >> Kolbers, > >> > >> > >> > >> Yesterday we finally were able to test run the HKS > engine > >> installation on my Firestar 2. The HKS engine started > right > >> up and ran, but it needed carburetor adjustment. I had > a > >> friend there who has experience with the HKS engine, > and he > >> was kind enough to adjust the carburetors using a dual > >> vacuum gauge. > >> > >> > >> > >> The one big issue I had was that the engine vibration > was > >> far far more than I was ever used to seeing on an > aircraft. > >> Part of this is that I'm "an airplane > guy" > >> instead of "an ultralight guy", Part of it is > that > >> the HKS is an opposed 2 cylinder engine with a very > high > >> compression ratio (11 to 1). But part of this is also > that > >> it did shake and vibrate a LOT, and I started thinking > about > >> how things tend to get loose and rattle apart in a > high > >> vibration environment. > >> > >> > >> > >> The one thing that really worried me is that around > idle > >> speed something became resonant and the wing struts > started > >> to vibrate up and down in the middle, maybe half an > inch up > >> and hald an inch down versus a straight line. Aluminum > does > >> NOT like this kind of vibration! Neither do fasteners. > After > >> about two minutes we shut the engine down, and someone > foun > >> the wing strut attachment pin (the short clevis pin) on > the > >> ground next to the airplane. I had put the pin in place > from > >> above without the safety pin )ground runs only). The > >> vibration backed the pin completely out! > >> > >> > >> > >> Does anyone else have this kind of wing strut vibration > with > >> the Kolb? > >> > >> > >> > >> Photos of the test run and adjustment wre posted here, > >> scroll halfway down the page to to post # 952 > >> > >> > >> > >> http://www.homebuiltairplanes. > >> com/forums/showthread.php?t > 28504&page=64&p=433039# > >> post433039 > >> > >> > >> > >> Bill Berle > >> > >> www.ezflaphandle.com > > >> - safety & performance upgrade for light aircraft > >> > >> www.grantstar.net > >> - winning proposals for non-profit and > for-profit > >> entities > >> > >> > >> > >> > >> > >> > > > > ==== ==================== ========== = > > -List" rel="noreferrer" > target="_blank">http://www.matronics.com/Navig > ator?Kolb-List > > ==== ==================== ========== = > > FORUMS - > > eferrer" > target="_blank">http://forums.matronics.com > > ==== ==================== ========== = > > WIKI - > > errer" > target="_blank">http://wiki.matronics.com > > ==== ==================== ========== = > > b Site - > > -Matt Dralle, List Admin. > > rel="noreferrer" > target="_blank">http://www.matronics.com/contr > ibution > > ==== ==================== ========== = > > > > > > > > > > > -- > =9CBlessed > are the cracked, for they shall let in the light.=9D Groucho > Marx > > > ________________________________ Message 3 _____________________________________ Time: 06:22:42 AM PST US From: Charlie England Subject: Re: Kolb-List: Firestar/HKS Engine Test Run I've not had a runout adjustment feature on any prop I've ever used, but with heavier homebuilts running Lycs & Conts, the SOP is to measure tracking, and shim between the engine's prop flange and the prop's mating surface to get equal tracking. Often, a strip of typing paper around the bolt circle arc on one side is enough to move the tip close to 1/8". I don't recall your prop brand/model, but if you're seeing 1/2" of static runout on a prop with a machined hub and blades made in molds, you could have either a defective prop, or a bent flange. On the other hand, if it's just out that much while running, it could just be balance, or unequal pitch among the blades, or slight runout made worse by running the engine. Static balance of the prop is a good first step, and relatively easy to do. Dynamic balance is better if you can beg/borrow a balancer, but if static balance and tracking are not right, the dynamic balancer may not be able to help you. Pusher props do see weird airflow; that's one reason fast pushers (VariEze, etc) don't have quite the speed gains over tractor designs that the calculations would suggest. But I've never heard of it causing such drastic prop oscillations. Charlie On Thu, Jul 5, 2018 at 3:23 AM, Bill Berle wrote: > > Thank you guys again for putting your brains on this :) > > A year ago I had contacted Jerry Olenik at Green Sky (RIP Jerry), and he > gave me a rough number of "something about 24 inches" between the exhaust > flange and the merge. That is what we built. I had actually sent HKS Japan > an e-mail and got no reply whatsoever (not even a rejection to my request > for info). That was disappointing, and not 100% professional on their part. > > The exhaust has a "restraining collar" bolted to the bolt that holds the > tailboom tube to the fuselage at the back of the cage. This restraint is > like a giant Adel clamp, except it has 1/8" gap around the exhaust pipe. > The concept (per my aero engineer) is to prevent the exhaust from moving > much or get into the prop, but to allow it to move a little so it can > adjust itself in the muffler due to movement and heat expansion. This > restraint is well below the flex joint, but before the pipe bends around > the tailboom towards the muffler. > > I have made arrangements to borrow a prop balancer, to at least eliminate > that as the culprit. I'm also going to re-pitch the prop, at the same time > as checking the runout. As mentioned, there's no runout adjustment on this > prop, so it may be moot. > > One other possibility for the runout is that as the prop blades pass near > the exhaust and the rear of the cage, there is a "dead spot" or eddy > current of air that allows that blade to see a little different in-flow or > out-flow, resulting in THAT blade making a little less or more thrust at > that instant, causing an aerodynamic fore-aft vibration (as opposed to a > mass balance problem). > > > Bill Berle > www.ezflaphandle.com - safety & performance upgrade for light aircraft > www.grantstar.net - winning proposals for non-profit and > for-profit entities > > -------------------------------------------- > On Wed, 7/4/18, Richard Girard wrote: > > Subject: Re: Kolb-List: Firestar/HKS Engine Test Run > To: "kolb-list@matronics.com" > Date: Wednesday, July 4, 2018, 9:34 PM > > Bill, I've been > flying in front of an HKS on my trike for 11 years. It does > not shake as you describe yours. Even when I first flew it > with the carbs significantly out of synch it was smooth. The > only shaking it does is on shutdown. Since you've > already synched the carbs it should run like a sewing > machine. Sorry I can't tell you anything more than your > engine is not running properly.I looked up the info I > got from the HKS group. > " Jim > Carruthers fabricated the exhaust system for my HKS when he > did the install on my Avid. We contacted HKS in Japan > about exhaust system requirements and received a reply back > from an HKS engineer. He said the headers need to merge at > 500mm for proper scavenging and the length after the > merge was not critical though he noted that installations > with excessively long pipes after the merge had experienced > rough idling issues. As far as individual headers with no > merge, there was an HKS on a Skyraider at OshKosh years ago > that had independent headers going to super trapp mufflers. > They had a difficult time getting the engine to run well and > it was way off on power. Jim routed my exhaust tubes to > merge as close to 500mm as room would allow in the cowling > and my engine runs fantastic. Right after the merge he > rolled a simple muffler can with no baffles and its pretty > quiet." > Hope this > helps,Rick > ________________________________ Message 4 _____________________________________ Time: 08:40:07 AM PST US From: "John Hauck" Subject: RE: Kolb-List: Firestar/HKS Engine Test Run Bill/Kolbers: Just a guess. Your exhaust system design is probably causing the vibration and the engine mounts are not able to absorb them, thus transmitting then to the airframe. With what little I know of your Kolb, I=99d say it is a combination of unconventional exhaust and engine mounts. My philosophy is KISS (keep it simple stupid). Your exhaust system goes way beyond KISS. If it can be disconnected at the =9CY=9D it might be a good idea to do that. Then test the engine isolated from all that exhaust plumbing. I believe everyone has given you good advice. I=99m guessing you are trying to silence the HKS with the fancy exhaust. I think you must remember that the prop makes much more noise than the engine. So...when it is all over and done, when your engine is silenced, you still have to contend with the whiny prop noise, a trade more of ultralights. I doubt the exhaust pipe in front of the prop is creating enough dead space to cause rough running. Kolbs have a lot more in front of the prop than just a small exhaust pipe. Just my early morning thoughts. Take it for what it is worth. High speed, low drag! ;-) John h Atlanta, GA -----Original Message----- From: owner-kolb-list-server@matronics.com [mailto:owner-kolb-list-server@matronics.com] On Behalf Of Bill Berle Sent: Thursday, July 5, 2018 3:24 AM. Subject: Re: Kolb-List: Firestar/HKS Engine Test Run victorbravo@sbcglobal.net> Thank you guys again for putting your brains on this :) A year ago I had contacted Jerry Olenik at Green Sky (RIP Jerry), and he gave me a rough number of "something about 24 inches" between the exhaust flange and the merge. That is what we built. I had actually sent HKS Japan an e-mail and got no reply whatsoever (not even a rejection to my request for info). That was disappointing, and not 100% professional on their part. The exhaust has a "restraining collar" bolted to the bolt that holds the tailboom tube to the fuselage at the back of the cage. This restraint is like a giant Adel clamp, except it has 1/8" gap around the exhaust pipe. The concept (per my aero engineer) is to prevent the exhaust from moving much or get into the prop, but to allow it to move a little so it can adjust itself in the muffler due to movement and heat expansion. This restraint is well below the flex joint, but before the pipe bends around the tailboom towards the muffler. I have made arrangements to borrow a prop balancer, to at least eliminate that as the culprit. I'm also going to re-pitch the prop, at the same time as checking the runout. As mentioned, there's no runout adjustment on this prop, so it may be moot. One other possibility for the runout is that as the prop blades pass near the exhaust and the rear of the cage, there is a "dead spot" or eddy current of air that allows that blade to see a little different in-flow or out-flow, resulting in THAT blade making a little less or more thrust at that instant, causing an aerodynamic fore-aft vibration (as opposed to a mass balance problem). Bill Berle www.ezflaphandle.com - safety & performance upgrade for light aircraft www.grantstar.net - winning proposals for non-profit and for-profit entities -------------------------------------------- On Wed, 7/4/18, Richard Girard < aslsa.rng@gmail.com> wrote: Subject: Re: Kolb-List: Firestar/HKS Engine Test Run kolb-list@matronics.com> Bill, I've been flying in front of an HKS on my trike for 11 years. It does not shake as you describe yours. Even when I first flew it with the carbs significantly out of synch it was smooth. The only shaking it does is on shutdown. Since you've already synched the carbs it should run like a sewing machine. Sorry I can't tell you anything more than your engine is not running properly.I looked up the info I got from the HKS group. " Jim Carruthers fabricated the exhaust system for my HKS when he did the install on my Avid. We contacted HKS in Japan about exhaust system requirements and received a reply back from an HKS engineer. He said the headers need to merge at 500mm for proper scavenging and the length after the merge was not critical though he noted that installations with excessively long pipes after the merge had experienced rough idling issues. As far as individual headers with no merge, there was an HKS on a Skyraider at OshKosh years ago that had independent headers going to super trapp mufflers. They had a difficult time getting the engine to run well and it was way off on power. Jim routed my exhaust tubes to merge as close to 500mm as room would allow in the cowling and my engine runs fantastic. Right after the merge he rolled a simple muffler can with no baffles and its pretty quiet." Hope this helps,Rick On Wed, Jul 4, 2018 at 9:43 PM, George Helton < gdhelton@gmail.com> wrote: George Helton < gdhelton@gmail.com> I put vg=99s on my Firestar a year ago. I did the bottom of horizontal stabilizers and the wings. They work well. George H. Firestar FS100, Hirth 2702 14GDH Mesick, Michigan gdhelton@gmail.com Sent from my iPhone > On Jul 4, 2018, at 6:34 PM, Bill Berle < victorbravo@sbcglobal.net> wrote: > victorbravo@sbcglobal.net> > > Thank you all for your input and opinions... I appreciate it. > > All that brightly colored junk lashed to the boom tube is the big tow strap that we used to tie the airplane to the Jeep. The tow strap looked big enough to lift a Sherman tank ! > > The 4" diameter silver tube under the tailboom is that Swiss Muffler I was talking about. Put it in the "woulda - coulda - shoulda worked" category. Regardless, I do need some sort of muffler, and this one actually works about as good as the stock HKS system, it just doesn't make a "wow!" difference like I thought it would. > > It is the tallest Kolb I've ever seen too... that was the big plan all along, to get the wing angle up high . Nothing was custom-built or scientifically researched about it... it's just a set of taller steel gear legs from the Kolb Slingshot, with 21 inch Desser bush tires. I'm not a tall guy by any means but I can get in and out OK. The trick is backing my butt up to the fuselage side, stepping on the tire, and hoisting myself up onto the side of the cockpit (longeron). It is a little easier than it looks. I WAS wondering if I was going to have to have a one rung rope ladder or step stool or toe strap or something to get in. Turns out I don't need it. > > Using the bottom of the wing as the reference, the airplane sits up at an 18 degree angle of attack (deck angle actually) when on the wheels. It's even a little more when it's on those roller skates that I use to move it in and out of the hangar. > > I will indeed check the propeller runout when I re-pitch it. It may be a moot point, there is apparently no adjustment that I can make to it. I do not believe the crankshaft is bent, and there is no visible damage to the propeller hub. > > In my own defense, the wing pins were only in temporarily, to get the wings out of the way of the propeller. The aircraft was NOT going to fly or even taxi on that day. > > I hope I'm not going to get any one upset or annoyed, but I have purchased a set of vortex generators for it, and those are going on ASAP. The VG's have now been shown to work well on the Kolb wing design, and several of the more experienced Kolbers seem to agree that they work as advertised. Because I have such a high grorund angle on mine, I would guess that my airplane would be even more prone to stalling on landing, doing the "Kolb Quit" maneuver. In order to get a 3 point landing I will probably have to pull the stick farther back than with other Kolbs, and wait a little longer before the tail comes all the way down. Which would put me at greater risk of that stall/drop. So the VG's will hopefully give me a little more margin while I am learning how to fly the airplane. > > Bill Berle > > > ------------------------------ -------------- > On Wed, 7/4/18, Charlie England < ceengland7@gmail.com> wrote: > > Subject: Re: Kolb-List: Firestar/HKS Engine Test Run > To: kolb-list@matronics.com > Date: Wednesday, July 4, 2018, 2:42 PM > > Hey Bill, > in that HBA link, you mentioned 1/2" of runout on the > prop. Did you check blade runout prior to engine start? That > much runout by itself could shake the engine off the plane. > A prop is a prop, UL or not, and if it isn't running > true, with exactly the same pitch on all blades, you're > going to get vibration. > Charlie > On Wed, Jul 4, 2018 at 4:15 > PM, George Helton < gdhelton@gmail.com> > wrote: > Well > Bill, I guess you should have learned a valuable lesson > about not only Kolbs but any aircraft. If you install a pin, > safety it, period. If you put a bolt in, put nut on it and > safety it. As far as the vibration goes, you=99ve got a wide > range on your idle setting. Don=99t worry about the rpm so > much as finding at sweet spot where it runs > smoothest. Is all that stuff you=99ve got lashed to > the boom tube the muffler you=99ve been telling us about? > Whew, sometimes our best ideas an efforts just don=99t seem > to work out. I=99ve been there before. I think that=99s the > tallest Kolb I=99ve ever seen. I=99m on the short side so > I=99d need a ladder just to get into the cockpit. Good > luck! George H.Firestar FS100, Hirth > 270214GDH Mesick, > Michigan gdhelton@gmail.com > > Sent > from my iPhone > On Jul 4, 2018, at > 3:03 PM, Rick Neilsen < neilsenrm@gmail.com> > wrote: > > Bill > I'm sure Larry will chime with > his HKS knowledge. > You need to get over that airplane > vs Ultralight thing. Vibrations are bad news. My redrive VW > runs smoother at cruise RPMs than any GA airplane I have > ever flown. > Most airplane engines have RPMs > that you stay away from or pass through quickly. The HKS is > known for its smoothness. I have to believe that what you > have experienced is torsional resonance. Take the prop off > and it will likely run smooth a silk. The higher the > compression and fewer the cylinders the harder it is to > tame. Geared engines are more prone to this issue but some > direct drive/prop engines have issues also. Internal > combustion engines will slow down on compression stroke and > speed up on ignition stroke. A prop wants to turn a constant > RPM. When a prop is subjected to these drastic changes in > RPM (resonance) the prop blades will whip around and do > nasty things and sometimes worse. All reduction drive > engines have some form of dampening device to reduce this > resonance but will likely not work sufficiently at all RPMs > (normally have more issues at idle RPMs). It is also > possible that engine/prop combination will not > work. > Worth what you paid for > it. > Rick NeilsenRedrive VW Powered > MKIIIC > On Wed, Jul > 4, 2018 at 1:20 PM Bill Berle < victorbravo@sbcglobal.net> > wrote: > Greetings > Kolbers, > > > > Yesterday we finally were able to test run the HKS engine > installation on my Firestar 2. The HKS engine started right > up and ran, but it needed carburetor adjustment. I had a > friend there who has experience with the HKS engine, and he > was kind enough to adjust the carburetors using a dual > vacuum gauge. > > > > The one big issue I had was that the engine vibration was > far far more than I was ever used to seeing on an aircraft. > Part of this is that I'm "an airplane guy" > instead of "an ultralight guy", Part of it is that > the HKS is an opposed 2 cylinder engine with a very high > compression ratio (11 to 1). But part of this is also that > it did shake and vibrate a LOT, and I started thinking about > how things tend to get loose and rattle apart in a high > vibration environment. > > > > The one thing that really worried me is that around idle > speed something became resonant and the wing struts started > to vibrate up and down in the middle, maybe half an inch up > and hald an inch down versus a straight line. Aluminum does > NOT like this kind of vibration! Neither do fasteners. After > about two minutes we shut the engine down, and someone foun > the wing strut attachment pin (the short clevis pin) on the > ground next to the airplane. I had put the pin in place from > above without the safety pin )ground runs only). The > vibration backed the pin completely out! > > > > Does anyone else have this kind of wing strut vibration with > the Kolb? > > > > Photos of the test run and adjustment wre posted here, > scroll halfway down the page to to post # 952 > > > > http://www.homebuiltairplanes. > com/forums/showthread.php?t 28504&page=64&p=433039# > post433039 > > > > Bill Berle > > www.ezflaphandle.com > - safety & performance upgrade for light aircraft > > www.grantstar.net > - winning proposals for non-profit and for-profit > entities > > > > > > ==== ===== = -List" rel="noreferrer" target="_blank"> http://www.matronics.com/Navig ator?Kolb-List ==== ===== = FORUMS - eferrer" target="_blank"> http://forums.matronics.com ==== ===== = WIKI - errer" target="_blank"> http://wiki.matronics.com ==== ===== = b Site - -Matt Dralle, List Admin. rel="noreferrer" target="_blank"> http://www.matronics.com/contr ibution ==== ===== = -- =9CBlessed are the cracked, for they shall let in the light.=9D Groucho Marx http://www.matronics.com/Navigator?Kolb-List http://www.matronics.com/contribution ________________________________ Message 5 _____________________________________ Time: 08:44:07 AM PST US From: "John Hauck" Subject: RE: Kolb-List: Firestar/HKS Engine Test Run Gary: Good info and remainder on carbon monoxide. You are absolutely correct, the tail boom is a leaf blower directed into the cockpit. Don=99t take a chance on CO2 poisoning. John h Atlanta, GA From: owner-kolb-list-server@matronics.com [mailto:owner-kolb-list-server@matronics.com] On Behalf Of Gary Aman Sent: Thursday, July 5, 2018 8:01 AM Subject: Re: Kolb-List: Firestar/HKS Engine Test Run just as an aside on your exhaust system,any exhaust that exits near the tube will travel along it and be drawn into the rear of the tube and blow into the cockpit like someone is back there with a leaf blower.I had to fashion a foam rubber plug to seal off the air flow up the tube, 6=9D thick with slits for the cables.The vg=99s are the way to go, even with my MK3C short spring steel gear legs,the tail wheel touches down first when I=99m solo. G.Aman MK3C Jabiru 2200A 1060hrs On Jul 5, 2018, at 4:23 AM, Bill Berle wrote: victorbravo@sbcglobal.net> Thank you guys again for putting your brains on this :) A year ago I had contacted Jerry Olenik at Green Sky (RIP Jerry), and he gave me a rough number of "something about 24 inches" between the exhaust flange and the merge. That is what we built. I had actually sent HKS Japan an e-mail and got no reply whatsoever (not even a rejection to my request for info). That was disappointing, and not 100% professional on their part. The exhaust has a "restraining collar" bolted to the bolt that holds the tailboom tube to the fuselage at the back of the cage. This restraint is like a giant Adel clamp, except it has 1/8" gap around the exhaust pipe. The concept (per my aero engineer) is to prevent the exhaust from moving much or get into the prop, but to allow it to move a little so it can adjust itself in the muffler due to movement and heat expansion. This restraint is well below the flex joint, but before the pipe bends around the tailboom towards the muffler. I have made arrangements to borrow a prop balancer, to at least eliminate that as the culprit. I'm also going to re-pitch the prop, at the same time as checking the runout. As mentioned, there's no runout adjustment on this prop, so it may be moot. One other possibility for the runout is that as the prop blades pass near the exhaust and the rear of the cage, there is a "dead spot" or eddy current of air that allows that blade to see a little different in-flow or out-flow, resulting in THAT blade making a little less or more thrust at that instant, causing an aerodynamic fore-aft vibration (as opposed to a mass balance problem). Bill Berle www.ezflaphandle.com - safety & performance upgrade for light aircraft www.grantstar.net - winning proposals for non-profit and for-profit entities -------------------------------------------- On Wed, 7/4/18, Richard Girard < aslsa.rng@gmail.com> wrote: Subject: Re: Kolb-List: Firestar/HKS Engine Test Run kolb-list@matronics.com> Bill, I've been flying in front of an HKS on my trike for 11 years. It does not shake as you describe yours. Even when I first flew it with the carbs significantly out of synch it was smooth. The only shaking it does is on shutdown. Since you've already synched the carbs it should run like a sewing machine. Sorry I can't tell you anything more than your engine is not running properly.I looked up the info I got from the HKS group. " Jim Carruthers fabricated the exhaust system for my HKS when he did the install on my Avid. We contacted HKS in Japan about exhaust system requirements and received a reply back from an HKS engineer. He said the headers need to merge at 500mm for proper scavenging and the length after the merge was not critical though he noted that installations with excessively long pipes after the merge had experienced rough idling issues. As far as individual headers with no merge, there was an HKS on a Skyraider at OshKosh years ago that had independent headers going to super trapp mufflers. They had a difficult time getting the engine to run well and it was way off on power. Jim routed my exhaust tubes to merge as close to 500mm as room would allow in the cowling and my engine runs fantastic. Right after the merge he rolled a simple muffler can with no baffles and its pretty quiet." Hope this helps,Rick On Wed, Jul 4, 2018 at 9:43 PM, George Helton < gdhelton@gmail.com> wrote: George Helton < gdhelton@gmail.com> I put vg=99s on my Firestar a year ago. I did the bottom of horizontal stabilizers and the wings. They work well. George H. Firestar FS100, Hirth 2702 14GDH Mesick, Michigan gdhelton@gmail.com Sent from my iPhone On Jul 4, 2018, at 6:34 PM, Bill Berle < victorbravo@sbcglobal.net> wrote: Thank you all for your input and opinions... I appreciate it. All that brightly colored junk lashed to the boom tube is the big tow strap that we used to tie the airplane to the Jeep. The tow strap looked big enough to lift a Sherman tank ! The 4" diameter silver tube under the tailboom is that Swiss Muffler I was talking about. Put it in the "woulda - coulda - shoulda worked" category. Regardless, I do need some sort of muffler, and this one actually works about as good as the stock HKS system, it just doesn't make a "wow!" difference like I thought it would. It is the tallest Kolb I've ever seen too... that was the big plan all along, to get the wing angle up high . Nothing was custom-built or scientifically researched about it... it's just a set of taller steel gear legs from the Kolb Slingshot, with 21 inch Desser bush tires. I'm not a tall guy by any means but I can get in and out OK. The trick is backing my butt up to the fuselage side, stepping on the tire, and hoisting myself up onto the side of the cockpit (longeron). It is a little easier than it looks. I WAS wondering if I was going to have to have a one rung rope ladder or step stool or toe strap or something to get in. Turns out I don't need it. Using the bottom of the wing as the reference, the airplane sits up at an 18 degree angle of attack (deck angle actually) when on the wheels. It's even a little more when it's on those roller skates that I use to move it in and out of the hangar. I will indeed check the propeller runout when I re-pitch it. It may be a moot point, there is apparently no adjustment that I can make to it. I do not believe the crankshaft is bent, and there is no visible damage to the propeller hub. In my own defense, the wing pins were only in temporarily, to get the wings out of the way of the propeller. The aircraft was NOT going to fly or even taxi on that day. I hope I'm not going to get any one upset or annoyed, but I have purchased a set of vortex generators for it, and those are going on ASAP. The VG's have now been shown to work well on the Kolb wing design, and several of the more experienced Kolbers seem to agree that they work as advertised. Because I have such a high grorund angle on mine, I would guess that my airplane would be even more prone to stalling on landing, doing the "Kolb Quit" maneuver. In order to get a 3 point landing I will probably have to pull the stick farther back than with other Kolbs, and wait a little longer before the tail comes all the way down. Which would put me at greater risk of that stall/drop. So the VG's will hopefully give me a little more margin while I am learning how to fly the airplane. Bill Berle ------------------------------ -------------- On Wed, 7/4/18, Charlie England wrote: Subject: Re: Kolb-List: Firestar/HKS Engine Test Run Hey Bill, in that HBA link, you mentioned 1/2" of runout on the prop. Did you check blade runout prior to engine start? That much runout by itself could shake the engine off the plane. A prop is a prop, UL or not, and if it isn't running true, with exactly the same pitch on all blades, you're going to get vibration. Charlie On Wed, Jul 4, 2018 at 4:15 PM, George Helton wrote: Well Bill, I guess you should have learned a valuable lesson about not only Kolbs but any aircraft. If you install a pin, safety it, period. If you put a bolt in, put nut on it and safety it. As far as the vibration goes, you=99ve got a wide range on your idle setting. Don=99t worry about the rpm so much as finding at sweet spot where it runs smoothest. Is all that stuff you=99ve got lashed to the boom tube the muffler you=99ve been telling us about? Whew, sometimes our best ideas an efforts just don=99t seem to work out. I=99ve been there before. I think that=99s the tallest Kolb I=99ve ever seen. I=99m on the short side so I=99d need a ladder just to get into the cockpit. Good luck! George H.Firestar FS100, Hirth 270214GDH Mesick, Michigan gdhelton@gmail.com Sent from my iPhone On Jul 4, 2018, at 3:03 PM, Rick Neilsen wrote: Bill I'm sure Larry will chime with his HKS knowledge. You need to get over that airplane vs Ultralight thing. Vibrations are bad news. My redrive VW runs smoother at cruise RPMs than any GA airplane I have ever flown. Most airplane engines have RPMs that you stay away from or pass through quickly. The HKS is known for its smoothness. I have to believe that what you have experienced is torsional resonance. Take the prop off and it will likely run smooth a silk. The higher the compression and fewer the cylinders the harder it is to tame. Geared engines are more prone to this issue but some direct drive/prop engines have issues also. Internal combustion engines will slow down on compression stroke and speed up on ignition stroke. A prop wants to turn a constant RPM. When a prop is subjected to these drastic changes in RPM (resonance) the prop blades will whip around and do nasty things and sometimes worse. All reduction drive engines have some form of dampening device to reduce this resonance but will likely not work sufficiently at all RPMs (normally have more issues at idle RPMs). It is also possible that engine/prop combination will not work. Worth what you paid for it. Rick NeilsenRedrive VW Powered MKIIIC On Wed, Jul 4, 2018 at 1:20 PM Bill Berle wrote: Greetings Kolbers, Yesterday we finally were able to test run the HKS engine installation on my Firestar 2. The HKS engine started right up and ran, but it needed carburetor adjustment. I had a friend there who has experience with the HKS engine, and he was kind enough to adjust the carburetors using a dual vacuum gauge. The one big issue I had was that the engine vibration was far far more than I was ever used to seeing on an aircraft. Part of this is that I'm "an airplane guy" instead of "an ultralight guy", Part of it is that the HKS is an opposed 2 cylinder engine with a very high compression ratio (11 to 1). But part of this is also that it did shake and vibrate a LOT, and I started thinking about how things tend to get loose and rattle apart in a high vibration environment. The one thing that really worried me is that around idle speed something became resonant and the wing struts started to vibrate up and down in the middle, maybe half an inch up and hald an inch down versus a straight line. Aluminum does NOT like this kind of vibration! Neither do fasteners. After about two minutes we shut the engine down, and someone foun the wing strut attachment pin (the short clevis pin) on the ground next to the airplane. I had put the pin in place from above without the safety pin )ground runs only). The vibration backed the pin completely out! Does anyone else have this kind of wing strut vibration with the Kolb? Photos of the test run and adjustment wre posted here, scroll halfway down the page to to post # 952 http://www.homebuiltairplanes. com/forums/showthread.php?t 28504&page=64&p=433039# post433039 Bill Berle www.ezflaphandle.com - safety & performance upgrade for light aircraft www.grantstar.net - winning proposals for non-profit and for-profit entities ==== ===== = -List" rel="noreferrer" target="_blank"> http://www.matronics.com/Navig ator?Kolb-List ==== ===== = FORUMS - eferrer" target="_blank"> http://forums.matronics.com ==== ===== = WIKI - errer" target="_blank"> http://wiki.matronics.com ==== ===== = b Site - -Matt Dralle, List Admin. rel="noreferrer" target="_blank"> http://www.matronics.com/contr ibution ==== ===== = -- =9CBlessed are the cracked, for they shall let in the light.=9D Groucho Marx http://www.matronics.com/Navigator?Kolb-List http://forums.matronics.com http://wiki.matronics.com http://www.matronics.com/contribution ________________________________ Message 6 _____________________________________ Time: 08:44:46 AM PST US From: "John Hauck" Subject: RE: Kolb-List: Firestar/HKS Engine Test Run Charlie: Used track wooden props on my US and FS with bond paper shims. Never needed to shim the WARP Drive props. They seem to be true or within 1/16=9D when they come from the factory. John h Atlanta, GA From: owner-kolb-list-server@matronics.com [mailto:owner-kolb-list-server@matronics.com] On Behalf Of Charlie England Sent: Thursday, July 5, 2018 8:13 AM Subject: Re: Kolb-List: Firestar/HKS Engine Test Run I've not had a runout adjustment feature on any prop I've ever used, but with heavier homebuilts running Lycs & Conts, the SOP is to measure tracking, and shim between the engine's prop flange and the prop's mating surface to get equal tracking. Often, a strip of typing paper around the bolt circle arc on one side is enough to move the tip close to 1/8". I don't recall your prop bran witd/model, but if you're seeing 1/2" of static runout on a prop with a machined hub and blades made in molds, you could have either a defective prop, or a bent flange. On the other hand, if it's just out that much while running, it could just be balance, or unequal pitch among the blades, or slight runout made worse by running the engine. Static balance of the prop is a good first step, and relatively easy to do. Dynamic balance is better if you can beg/borrow a balancer, but if static balance and tracking are not right, the dynamic balancer may not be able to help you. Pusher props do see weird airflow; that's one reason fast pushers (VariEze, etc) don't have quite the speed gains over tractor designs that the calculations would suggest. But I've never heard of it causing such drastic prop oscillations. Charlie On Thu, Jul 5, 2018 at 3:23 AM, Bill Berle wrote: Thank you guys again for putting your brains on this :) A year ago I had contacted Jerry Olenik at Green Sky (RIP Jerry), and he gave me a rough number of "something about 24 inches" between the exhaust flange and the merge. That is what we built. I had actually sent HKS Japan an e-mail and got no reply whatsoever (not even a rejection to my request for info). That was disappointing, and not 100% professional on their part. The exhaust has a "restraining collar" bolted to the bolt that holds the tailboom tube to the fuselage at the back of the cage. This restraint is like a giant Adel clamp, except it has 1/8" gap around the exhaust pipe. The concept (per my aero engineer) is to prevent the exhaust from moving much or get into the prop, but to allow it to move a little so it can adjust itself in the muffler due to movement and heat expansion. This restraint is well below the flex joint, but before the pipe bends around the tailboom towards the muffler. I have made arrangements to borrow a prop balancer, to at least eliminate that as the culprit. I'm also going to re-pitch the prop, at the same time as checking the runout. As mentioned, there's no runout adjustment on this prop, so it may be moot. One other possibility for the runout is that as the prop blades pass near the exhaust and the rear of the cage, there is a "dead spot" or eddy current of air that allows that blade to see a little different in-flow or out-flow, resulting in THAT blade making a little less or more thrust at that instant, causing an aerodynamic fore-aft vibration (as opposed to a mass balance problem). Bill Berle www.ezflaphandle.com - safety & performance upgrade for light aircraft www.grantstar.net - winning proposals for non-profit and for-profit entities -------------------------------------------- On Wed, 7/4/18, Richard Girard wrote: Subject: Re: Kolb-List: Firestar/HKS Engine Test Run To: "kolb-list@matronics.com" Date: Wednesday, July 4, 2018, 9:34 PM Bill, I've been flying in front of an HKS on my trike for 11 years. It does not shake as you describe yours. Even when I first flew it with the carbs significantly out of synch it was smooth. The only shaking it does is on shutdown. Since you've already synched the carbs it should run like a sewing machine. Sorry I can't tell you anything more than your engine is not running properly.I looked up the info I got from the HKS group. " Jim Carruthers fabricated the exhaust system for my HKS when he did the install on my Avid. We contacted HKS in Japan about exhaust system requirements and received a reply back from an HKS engineer. He said the headers need to merge at 500mm for proper scavenging and the length after the merge was not critical though he noted that installations with excessively long pipes after the merge had experienced rough idling issues. As far as individual headers with no merge, there was an HKS on a Skyraider at OshKosh years ago that had independent headers going to super trapp mufflers. They had a difficult time getting the engine to run well and it was way off on power. Jim routed my exhaust tubes to merge as close to 500mm as room would allow in the cowling and my engine runs fantastic. Right after the merge he rolled a simple muffler can with no baffles and its pretty quiet." Hope this helps,Rick ________________________________ Message 7 _____________________________________ Time: 10:02:27 AM PST US Subject: Re: Kolb-List: Firestar/HKS Engine Test Run From: Charlie England I agree; there's no reason for a Warp Drive or similar design with 'made in a mold' blades and a machined hub to have any runout, unless it's defective, or the drive's prop flange is bent. Charlie On 7/5/2018 10:44 AM, John Hauck wrote: > > Charlie: > > Used track wooden props on my US and FS with bond paper shims. > > Never needed to shim the WARP Drive props. They seem to be true or > within 1/16 when they come from the factory. > > John h > > Atlanta, GA > > *From:*owner-kolb-list-server@matronics.com > [mailto:owner-kolb-list-server@matronics.com] *On Behalf Of *Charlie > England > *Sent:* Thursday, July 5, 2018 8:13 AM > *To:* kolb-list@matronics.com > *Subject:* Re: Kolb-List: Firestar/HKS Engine Test Run > > I've not had a runout adjustment feature on any prop I've ever used, > but with heavier homebuilts running Lycs & Conts, the SOP is to > measure tracking, and shim between the engine's prop flange and the > prop's mating surface to get equal tracking. Often, a strip of typing > paper around the bolt circle arc on one side is enough to move the tip > close to 1/8". I don't recall your prop branwitd/model, but if you're > seeing 1/2" of static runout on a prop with a machined hub and blades > made in molds, you could have either a defective prop, or a bent > flange. On the other hand, if it's just out that much while running, > it could just be balance, or unequal pitch among the blades, or slight > runout made worse by running the engine. > > Static balance of the prop is a good first step, and relatively easy > to do. Dynamic balance is better if you can beg/borrow a balancer, but > if static balance and tracking are not right, the dynamic balancer may > not be able to help you. > > Pusher props do see weird airflow; that's one reason fast pushers > (VariEze, etc) don't have quite the speed gains over tractor designs > that the calculations would suggest. But I've never heard of it > causing such drastic prop oscillations. > > Charlie > > On Thu, Jul 5, 2018 at 3:23 AM, Bill Berle > wrote: > > > > > Thank you guys again for putting your brains on this :) > > A year ago I had contacted Jerry Olenik at Green Sky (RIP Jerry), and > he gave me a rough number of "something about 24 inches" between the > exhaust flange and the merge. That is what we built. I had actually > sent HKS Japan an e-mail and got no reply whatsoever (not even a > rejection to my request for info). That was disappointing, and not > 100% professional on their part. > > The exhaust has a "restraining collar" bolted to the bolt that holds > the tailboom tube to the fuselage at the back of the cage. This > restraint is like a giant Adel clamp, except it has 1/8" gap around > the exhaust pipe. The concept (per my aero engineer) is to prevent the > exhaust from moving much or get into the prop, but to allow it to move > a little so it can adjust itself in the muffler due to movement and > heat expansion. This restraint is well below the flex joint, but > before the pipe bends around the tailboom towards the muffler. > > I have made arrangements to borrow a prop balancer, to at least > eliminate that as the culprit. I'm also going to re-pitch the prop, at > the same time as checking the runout. As mentioned, there's no runout > adjustment on this prop, so it may be moot. > > One other possibility for the runout is that as the prop blades pass > near the exhaust and the rear of the cage, there is a "dead spot" or > eddy current of air that allows that blade to see a little different > in-flow or out-flow, resulting in THAT blade making a little less or > more thrust at that instant, causing an aerodynamic fore-aft vibration > (as opposed to a mass balance problem). > > > Bill Berle > www.ezflaphandle.com - safety & > performance upgrade for light aircraft > www.grantstar.net - winning proposals > for non-profit and for-profit entities > > -------------------------------------------- > On Wed, 7/4/18, Richard Girard > wrote: > > Subject: Re: Kolb-List: Firestar/HKS Engine Test Run > To: "kolb-list@matronics.com " > > > Date: Wednesday, July 4, 2018, 9:34 PM > > Bill, I've been > flying in front of an HKS on my trike for 11 years. It does > not shake as you describe yours. Even when I first flew it > with the carbs significantly out of synch it was smooth. The > only shaking it does is on shutdown. Since you've > already synched the carbs it should run like a sewing > machine. Sorry I can't tell you anything more than your > engine is not running properly.I looked up the info I > got from the HKS group. > "Jim > Carruthers fabricated the exhaust system for my HKS when he > did the install on my Avid. We contacted HKS in Japan > about exhaust system requirements and received a reply back > from an HKS engineer. He said the headers need to merge at > 500mm for proper scavenging and the length after the > merge was not critical though he noted that installations > with excessively long pipes after the merge had experienced > rough idling issues. As far as individual headers with no > merge, there was an HKS on a Skyraider at OshKosh years ago > that had independent headers going to super trapp mufflers. > They had a difficult time getting the engine to run well and > it was way off on power. Jim routed my exhaust tubes to > merge as close to 500mm as room would allow in the cowling > and my engine runs fantastic. Right after the merge he > rolled a simple muffler can with no baffles and its pretty > quiet." > Hope this > helps,Rick > --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message kolb-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Kolb-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/kolb-list Browse Digests http://www.matronics.com/digest/kolb-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.