---------------------------------------------------------- Kolb-List Digest Archive --- Total Messages Posted Mon 10/25/10: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:12 AM - slingshot thrust line (Ted Cowan) 2. 05:13 AM - Re: Another video.. (Thom Riddle) 3. 06:53 AM - Re: Re: Another video.. (Jack B. Hart) 4. 06:56 AM - proper thrustline (Mike Welch) 5. 07:17 AM - Re: Another video.. (Thom Riddle) 6. 09:13 AM - Re: proper thrustline (John Hauck) 7. 09:44 AM - Re: Slingshot thrust line/angle/HKS (McCarthy Tom) 8. 10:54 AM - Re: Kolb-List Digest: 12 Msgs - 10/24/10 (Bob Green) 9. 05:21 PM - Re: SPOT Working (Roger Lee) 10. 10:46 PM - Re: slingshot thrust line () ________________________________ Message 1 _____________________________________ Time: 03:12:17 AM PST US From: "Ted Cowan" Subject: Kolb-List: slingshot thrust line I am going to jump in here because I believe the SS has the engine thrust line too far back. I hope you get this pic of my SS with the 912. The 582 had about the same thrust line as my 912 only adjusted for the power. If you dont raise the back of the engine on the mount you will be virtually pushing the nose over. The entire airframe will be fighting. You MUST raise the rear mounts from 3/4 to maybe 7/8 of an inch (one guy went more than that) in order to correct the angle of attack. I bet you have a really heavy stick or a lot of bungee stretch to compensate. At 7/8 at the rear of the mounts, you will be able to fly virtually hands off at your regular cruise rate and not have to fight it on take off. I bet you got a handful when you firewall the engine at take off. Not just my opinion, fact on this one and if you dont believe, well, fight it in the air. Raise the rear of the engine a little at a time and you will see the difference in the first quarter inch. You will notice the angle of the blade in relation to the boom. This really works. Trust me. Ted Cowan, Slingshot, 912UL, zoom zoom ________________________________ Message 2 _____________________________________ Time: 05:13:30 AM PST US Subject: Kolb-List: Re: Another video.. From: "Thom Riddle" Richard, I wish it were that simple. The Jab motor mount attaches to the standard Kolb motor mount plates with matching plates which would require beveled shims under the front and rear mounts to be done right, as well as the correct length AN bolts. I'd like to get close to the right answer the first try so I don't have to fabricate several different angle/thickness shims and purchase several different length AN bolts. I think I'll just assume that the correct angle for the thrust line is parallel to the horizontal stabilizer and go with that. That angle has got to be better than what it is now. -------- Thom Riddle Buffalo, NY (9G0) Kolb Slingshot SS-021 Jabiru 2200A #1574 Tennessee Prop 64x32 Everyone is entitled to his own opinion, but not his own facts. Daniel Patrick Moynihan Read this topic online here: http://forums.matronics.com/viewtopic.php?p=316943#316943 ________________________________ Message 3 _____________________________________ Time: 06:53:25 AM PST US From: "Jack B. Hart" Subject: Re: Kolb-List: Re: Another video.. Thom, I agree with Richard Pike. If one assumes the wing aoa is six degrees and your engine is set 3.5 degrees on top of that, and using the cosine of 9.5 degree, it indicates that 98.6 % of your thrust is pushing in the direction of the relative wind. The other right angle thrust component is being used to help hold up the plane. Agreed 1.5% loss is not very much and your plane should climb better than if the thrust vector was set in the direction of the relative wind. By reseting the engine, you should gain some cruise speed, and reduce cruise power factor and fuel flow with less trim. The question is, is it worth the effort to capture a couple of horsepower? Jack B. Hart FF004 Winchester, IN ________________________________ Message 4 _____________________________________ Time: 06:56:13 AM PST US From: Mike Welch Subject: Kolb-List: proper thrustline Thom=2C (I changed the subject line to correctly reflect the topic) One year ago=2C our fellow comrade John Ratcliffe and I had several priva te messages regarding his wing's incidences on his MkIII Xtra. John drew up a nice com puter generated stick figure Xtra with ALL the appropriate digital angles that the Xtra is supposed to have. (tailfeathers=2C boomtube=2C motor mount=2C etc) One thing he and I were NOT completely sure of is=3B if you rotate that s tick drawing for say...the tailfeathers to be zero degrees=2C this will give you a certain n ew reading for the rest of the planes angles. Now=2C what if you rotate that stick figure instead from the main wing's as you pivot point=2C to where the main wings incidence is now zero? Will that give you an exact change in the tailfeather's incidence as you got with the main wings? I am NOT sure. What I'm getting at is that it MAY not be as simple as adding or subtract ing one angle setting from another by simple mathematics. Frankly=2C I'd need proof that by simp ly rotating the airplane from the wheels as a pivot point that ALL other angles change in an equal a mount compared to if you rotated the plane by the main wings. Between John and I=2C we never really did figure out if it mattered. May be it doesn't matter whether you pivot the plane by the wheels=2C or the tail=2C or the main wings (to g et all the different incidence readings). What I'm getting at is unless I saw for my own eyes that by simple additi on and subtraction you could figure out one reading compared to another=2C I would have to phy sically reposition the plane=2C and take a reading=2C before I'd accept that that were true! Maybe it's just me=2C but I want proof!! Your example of=3B Tail Boom = 5 degrees (front higher) Horizontal Stabilizer = 5 deg. (front higher) parallel to boom Wing Bottom = 12 degrees Engine Thrust Line = 15.5 degrees Therefore=2C relative to the Horizontal Stabilizer.... Wing Bottom has a 7 degrees incidence (12 - 5) Engine Thrust line has 10.5 degrees incidence (15.5 -5) Unless I saw this was the case=2C I wouldn't automatically and necessaril y believe it. One thing I can guarantee I'd do=2C if it were me=2C I'd go with the fact ory recommendations on how to set up your planes angles. On the MkIII=2C you set the motor mount to zero=2C and all other angles go from there. I imagine the SlingShot does too. After all=2C unless you first establish that the motor mount is zero=2C a nd then take all your reading=2C for all you know=2C maybe the engine thrust line is correct and the main wi ng's incidence is wrong! The photos supplied by Chris show his plane in the initial factory recomm ended position=2C where all other incidences are to be set. I'd do that first=2C and then determin e where to proceed. (You probably were going to do this anyway) I could be completely in the dark on this=2C but that's how I see it. ( you appear to have a digital level) I also wouldn't change a thin washer without taking precise (!!) re adings of where everything is at the moment!! This is a good topic=2C with lots of experiences pilots weighing in. Pro per Kolb flying surface settings are always an important topic for me. Mike Welch MkIIICX ________________________________ Message 5 _____________________________________ Time: 07:17:46 AM PST US Subject: Kolb-List: Re: Another video.. From: "Thom Riddle" Jack, I did the math too and that is the reason I've not been in a hurry to do the work, but think I will eventually get around to it. The other problem with this that Chris alluded to is that the point and angle at which the thrust is acting is so far aft of the CG that it results in a significant nose down pitching moment when adding power, more so I believe than if the thrust was parallel to relative wind. The net result of this torque about the CG is an effectively heavier wing (at CG) requiring more tail down force to counter. So the loss in direct thrust is only part of the net negative effect. Relieving the wing of the extra thrust angle induced load and the extra HS loading is worthwhile also. Perhaps I am visualizing this all wrong, so if you would like to correct me with your excellent vector diagrams, I'm all ears and eyes. Or if I am correct, your confirmation is welcome too :-). When I get around to doing it, I'll report the qualitative and quantitive results, if any. -------- Thom Riddle Buffalo, NY (9G0) Kolb Slingshot SS-021 Jabiru 2200A #1574 Tennessee Prop 64x32 Everyone is entitled to his own opinion, but not his own facts. Daniel Patrick Moynihan Read this topic online here: http://forums.matronics.com/viewtopic.php?p=316962#316962 ________________________________ Message 6 _____________________________________ Time: 09:13:53 AM PST US From: "John Hauck" Subject: Re: Kolb-List: proper thrustline Mike W/Gang: I agree with the statement below, build the Kolb according to plans and instructions. Test fly it, get some hours on it, get the feel of the airplane, then make minute changes. However, make one change at a time, then test fly to verify what you changed. Many of you all are building Kolbs, have never flown one, and, for sure, have never flown the airplane you are building. Making a lot of changes based on what someone else did to their airplane, especially another model Kolb, is not wise, in my humble opinion. You will not know how your particular Kolb will fly until you fly it. However, if built to plans, it will fly well. Maybe need a tiny bit of tweaking, but not much to please the builder/pilot. When experimenting with angles of thrust, don't forget the attitude of the engine on the ground, with the engine stopped, will not be the same as the angle of thrust when the engine is flying at and producing cruise power. Depending on the engine, Rotax two or four stroke, or other engines, the prop will be turning either clockwise or counter clockwise. The thrust will cause the rear of the engine to rise and depress the front of the engine, more left front or right front, depending on which way the prop turns. Depending on the desity of the Lord Mount (on a standard Kolb configured engine mount) the change in angle of thrust will be significant. If you doubt me, then tie down your Kolb, while observing the engine, go to full power and watch the engine change position on the mounts as you change power settings. Recommend you insure you have the most dense Lord Mounts on your airplane no matter what engine you are flying with. Take care, john h mkIII Rock House, Oregon One thing I can guarantee I'd do, if it were me, I'd go with the factory recommendations on how to set up your planes angles. Mike Welch ________________________________ Message 7 _____________________________________ Time: 09:44:57 AM PST US From: McCarthy Tom Subject: Re: Kolb-List: Slingshot thrust line/angle/HKS Thom, I have done a lot of experimenting with thrust angle and thrust height on my slingshot. Most of it started after I installed the Rotax 532 on my Slingshot and received help and advice from Ted Cowen. If you email me your ph# and a good time to call, I will talk about it off list due to the amount of content involved. As far as the testing with the Slingshot/HKS is going, I'm kind of at a stand still. I'm having problems with EGT and CHT going to high. I think it is due to my custom exhaust or a ram air effect due to a forward carb style. Work and weather are slowing progress down as well. If it were not for the high temp problems, my experimenting would be complete. I have turned the gear box down, added more height to the rear mount bringing it up about 1 1/2" total, so the thrust line is parallel to the flight line, and the 68" 3 blade Warp prop is about 3/4" from the boom tube. The result is very nice. I will report the actual numbers when I confirm with a GPS. Early numbers are 4800rpm, cruise at 55mph, 5800rpm, cruise at 80mph, with climb 700fpm, with only slight back pressure through out the power range(no trim tab yet) Tom McCarthy N514 TM Zenith 601HD N414 TM Kolb Firestar N863 GB Kolb Slingshot ________________________________ Message 8 _____________________________________ Time: 10:54:56 AM PST US From: Bob Green Subject: Kolb-List: RE: Kolb-List Digest: 12 Msgs - 10/24/10 So glad your friend survived the car crash. Muchas gracias por la informacin en cuanto a SPOT. Cul Kolb tienes? Tengo (en via de construccin) una Mark IIIX. Chow. Bob Green Time: 07:22:17 AM PST US Subject: Kolb-List: SPOT Working From: "henry.voris" 22oct10 Tuxtla Gutierrez, Mexico Fortunately at the time of the crash the emergency helicopter was overhead. So by the time we reached the wreck they had cut our driver out of the car and evacuated him to the hospital in Tuxtla (unconscious with a broken leg, bruised and cut). I have included Before and After photos... Worth what you paid for it... and I hope your mileage will differ... Aloha -------- Henry Firefly Five-Charlie-Bravo ________________________________ Message 9 _____________________________________ Time: 05:21:27 PM PST US Subject: Kolb-List: Re: SPOT Working From: "Roger Lee" I'm flying to Yuma, AZ again tomorrow, Tuesday at 0830 Mountain Time or AZ. time today. You can track me as I go. I will leave at 0830 and arrive in Yuma at approximately 1030. I come home Friday late afternoon at 1530 hrs. and will be back in Tucson at 1730 hrs. mountain time. You can follow me by clicking on the link above where it has my Spot Tracker link. http://share.findmes...4WO25eB0VkBu5Iv -------- Roger Lee Tucson, Az. Light Sport Repairman - Maintenance Rated Rotax Repair Center 520-574-1080 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=317034#317034 ________________________________ Message 10 ____________________________________ Time: 10:46:44 PM PST US From: Subject: Re: Kolb-List: slingshot thrust line Yep that worked for me on the MK111c. Packed the back up with 2 washers. There is a slight pitch up when you throttle back from cruse rpm by about 200 rpm . The pitch up is so slight that it is no more than a "be aware this will happen" it is normal, when some one is flying the Kolb for the first time . I was trying to get the prop away from the boom at the bottom to reduce noise. Not sure that worked , but I like the way it fly's now . I have never measured the angles . Just changed things a little and went flying . Down under MK111c ------------------------------------------------------------------------------------- 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.