---------------------------------------------------------- Kolb-List Digest Archive --- Total Messages Posted Mon 02/20/12: 22 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:21 AM - Re: Re: Making touchdown with high thrustline? (Pat Ladd) 2. 04:48 AM - Re: Making touchdown with high thrustline? (Ducati SS) 3. 04:58 AM - Re: Kolb quit revealed (Pat Ladd) 4. 05:01 AM - Re: Re: Making touchdown with high thrustline? (Pat Ladd) 5. 06:28 AM - Re: Re: frunt mounted radiator (Charlie England) 6. 07:29 AM - Re: Kolb quit revealed (vic) 7. 08:58 AM - Re: belt reduction (Thumper) 8. 09:09 AM - stall?????? (b young) 9. 09:26 AM - Re: stall?????? (vic) 10. 11:00 AM - Re: belt reduction (Ducati SS) 11. 11:29 AM - Re: Kolb quit revealed (Pat Ladd) 12. 02:54 PM - rotax377 (chris davis) 13. 03:03 PM - NI-CAD (chris davis) 14. 03:23 PM - Re: NI-CAD (Herb Gayheart) 15. 04:29 PM - Re: NI-CAD (Charlie England) 16. 05:13 PM - M3c first flight, no kolb quit (awcbs) 17. 05:20 PM - Re: rotax377 (Dana Hague) 18. 06:36 PM - Re: M3c first flight, no kolb quit (kinne russ) 19. 07:33 PM - NI-CAD (Jack B. Hart) 20. 08:29 PM - Re: M3c first flight, no Kolb quit (John Hauck) 21. 08:52 PM - Re: rotax377 (chris davis) 22. 09:00 PM - Re: NI-CAD (chris davis) ________________________________ Message 1 _____________________________________ Time: 03:21:09 AM PST US From: "Pat Ladd" Subject: Re: Kolb-List: Re: Making touchdown with high thrustline? No need to bounce airspeed up and down.Then if you find a field close by you can circle down or otherwise bleed energy.If I am dead stick I would rather let trim take care of speed wile I look for a suitable landing area.>> Hi, In my experience it is the surrounding air which is `bouncing the airspeed up and down` not the pilot. He is usually busy correcting for the wind induced speed variation. `Trim for speed?` I suppose in the still of an evening that might be possible. Probably not in normal flight conditions. Trim, in aircraft with as little inertia as ours would not maintain your speed reliably enough for you to `look around for a landing field` I always trim nose heavy so that when I am `looking around` even on a normal approach the tendency is for speed to increase NOT wander towards a stall. Regarding `looking around for a place to land`. I remember flying in a Jackaroo (a Tiger Moth with a lid on) with a very experienced pilot. In fact he later became World Gliding Champion. We were in the cruise and I said "If the engine quit now where would we land` Without a moments hesitation he said `There` pointing at the ground 1500 feet directly below us. I have only lost power twice. Once at about 300 ft agl on the approach. Nowhere to go except the field full of cows directly in front of me. Once at around 1000ft agl. Time moves quickly. There are a few seconds lost while the fact that your power has gone registers. A bit more while you sort out your airspeed and get the nose down Where is the wind? Is there time to turn into wind anyway?. Probably not. Is there a field at all. In the UK there usually is but it will usually be small with surrounding walls or hedges. Will you make the field you want? The thing I miss in the Kolb is being unable to side slip. Well, you can but it doesn`t achieve much. Previously I was able to maintain a clean wing and side slip height off. Kick straight and be back in a reasonable glide angle. Much simpler that putting flaps up and down. By the time you have sorted that lot out you are at 50ft or less going like a bat out of hell because you don`t want to stall You will probably not make a tidy landing. I arrived on the ground with brakes full on (the advantage of tricycle undercart) in a cloud of dust with the far wall approaching fast. You will spend a lot of time afterwards wondering what you did wrong. Probably nearly everything. What you did right. Well!. You walked away (With luck)What you can improve.Practice dead stick and EXPECT to lose an engine. In a glider until you get very experienced you will always know where the wind is coming from and you will have a field picked out where you will land if you can`t work the last thermal. And you will probably have a 10 mile radius to search over from 1500ft. In a Kolb from a 1000ft your time and field choices are strictly limited. Part of the trouble is that engines are now so much improved that we no longer fly expecting the engine to quit Perhaps we should. New pilots beginning to fly now will probably never experience an engine out whereas the older guys expected the engine to fail .That awareness bought that extra few seconds which you desperately need in those circumstances. Cheers Pat ________________________________ Message 2 _____________________________________ Time: 04:48:42 AM PST US Subject: Kolb-List: Re: Making touchdown with high thrustline? From: "Ducati SS" Best glide speed is usually a fair bit higher than stall. Every mph above best glide speed will shorten the glide distance and reduce landing options. obviously rough air and wind will require corrections but a well designed airplane will always return to its trimmed speed. Yes our lightweight airplanes are like a leaf in the breeze and sometimes require a different technique. My comments were of a general nature. We lost a local UL pilot not long ago, last sighting had him unusually low. We may never know what happened but I often wounder how many of these crashes are caused when the pilot finds he is low and slow and tries to arrest the descent with pitch instead of power. Way back in 1980 when I was taking flying lessons I paid little attention to engine out proceedures, I thought this is an airplane engine it won't ever quit. Well in the years since I have been shocked at how many pilots have had engine failures. I had an 0200 lose power on climb out ( fortunately it recovered on it,s own ) and then days later quit just after touch down. I expect every engine in every piece of equipment I operate to quit at some point. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=366690#366690 ________________________________ Message 3 _____________________________________ Time: 04:58:56 AM PST US From: "Pat Ladd" Subject: Re: Kolb-List: Kolb quit revealed Stall tests with 2 pass indicated 30. 2 mph higher than with 1 pass. Vic, I don`t understand. You seem to be saying that with one up you stall at 28. With 2 up you stall at 30 (2mph higher) The trend seems to be right. If you are heavier you will stall at a higher speed. You then go on to say that you DONT stall with 2 up at 40. I don`t understand what that has to do with anything. It would seem that you are comparing stalling speeds when you are landing. I would not have thought that was the ideal way to make a comparison. There are too many variable introduced by doing tests in ground effect and the variations which must be introduced in flying the machine to a safe touchdown. I would suggest comparison should take place at a safe altitude in quiet evening air and the stall should be approached with the application of back stick using the same time/movement frame. Standard measurement exist for this.The mean of a series of tests should give a more accurate picture. I would have expected the addition of a passenger (198 lbs is the accepted standard weight of a crewman here in the UK I believe) to have produced a bigger difference in stall speed. Rule of thumb, I would have flown faster Surely someone on the list can produce the math. Not my forte. It would take me a month Pat ________________________________ Message 4 _____________________________________ Time: 05:01:53 AM PST US From: "Pat Ladd" Subject: Re: Kolb-List: Re: Making touchdown with high thrustline? how many of these crashes are caused when the pilot finds he is low and slow and tries to arrest the descent with pitch instead of power. It takes a lot of willpower NOT to pull the nose up when you see the ground looming up. Its the natural thing to do. Pat ________________________________ Message 5 _____________________________________ Time: 06:28:51 AM PST US From: Charlie England Subject: Re: Kolb-List: Re: frunt mounted radiator Many thanks! On 02/19/2012 11:45 PM, Richard Girard wrote: > Charlie, It's about 95.5 sq.in . (11 X 8.7) and the core > is an inch thick. It's about 14 inches wide including the tanks. > > Rick > > On Fri, Feb 17, 2012 at 3:21 PM, Charlie England > > wrote: > > Hi Rick, > > Next time you're at the plane, would you mind getting some > measurements? I'd like to know the face area & thickness of the > core itself, and also the overall dimensions including the tanks > (not including fittings, hoses, etc). > > Thanks, > > Charlie > > > On 02/17/2012 01:06 PM, Richard Girard wrote: >> Richard, I have put the Honda Magna radiator on two Kolb Mk >> III's now. I have a 1/2 mile taxi when the wind is from the south >> and have never had an overheat situation with either airplane >> even in last summer's 115+ temperatures. If it was a problem, I >> think I'd have seen it by now. The Mark III has enough issue with >> in flow to the prop without putting a radiator right in front. >> The Magna radiator also has provision for a cooling fan if it was >> required, but so far there has been no need. >> I have had overheat issues with the stock Rotax radiators mounted >> in front of the engine and at the gearbox. That was what started >> me on the trail to a single radiator. That, and the expense. >> >> Rick Girard >> >> On Fri, Feb 17, 2012 at 11:03 AM, Richard Pike >> > wrote: >> >> > >> >> Why do you want one at that end? I tried that the first year >> I had my MKIII, and noticed two things: if you were unable to >> take off as soon as you wanted, the engine would overheat, >> and it also seemed to hurt the rate of climb. I like having >> the radiator just ahead of the prop so that the temps stay >> normal while taxiing. >> >> I do currently have a small radiator just in front of the air >> filter/silencer box to augment the main radiator that is >> behind and under the wing/in front of the prop, as the >> original was not quite enough in July & August. I can post >> pictures if you are interested. >> >> -------- >> Richard Pike >> Kolb MKIII N420P (420ldPoops) >> richard (at) bcchapel(dot)org >> Kingsport, TN 3TN0 >> Now faith is the substance of things hoped for, the evidence >> of things not seen. >> Hebrews 11:1 >> >> >> >> >> Read this topic online here: >> >> http://forums.matronics.com/viewtopic.php?p=366484#366484 >> >> >> >> >> >> >> >> ========== >> arget="_blank">http://www.matronics.com/Navigator?Kolb-List >> ========== >> http://forums.matronics.com >> ========== >> le, List Admin. >> ="_blank">http://www.matronics.com/contribution >> ========== >> >> >> >> >> >> >> -- >> Zulu Delta >> Mk IIIC >> Thanks, Homer GBYM >> >> It isn't necessary to have relatives in Kansas City in order to >> be unhappy. >> - Groucho Marx >> >> >> * >> >> >> * > > * > > get="_blank">http://www.matronics.com/Navigator?Kolb-List > tp://forums.matronics.com > _blank">http://www.matronics.com/contribution > > * > > > -- > Zulu Delta > Mk IIIC > Thanks, Homer GBYM > > It isn't necessary to have relatives in Kansas City in order to be > unhappy. > - ________________________________ Message 6 _____________________________________ Time: 07:29:54 AM PST US From: "vic" Subject: Re: Kolb-List: Kolb quit revealed Pat I did do stall tests at altitude. 28mph pilot only. Landing straight and level,not diving, just letting that last 3 or 4 ft. diminish it stalls at 35mph single, 40....2 up. Unless I drop the tail.... then 28mph stall. The only thing that makes sense is ground effect. ----- Original Message ----- From: Pat Ladd To: kolb-list@matronics.com Sent: Monday, February 20, 2012 7:58 AM Subject: Re: Kolb-List: Kolb quit revealed Stall tests with 2 pass indicated 30. 2 mph higher than with 1 pass. Vic, I don`t understand. You seem to be saying that with one up you stall at 28. With 2 up you stall at 30 (2mph higher) The trend seems to be right. If you are heavier you will stall at a higher speed. You then go on to say that you DONT stall with 2 up at 40. I don`t understand what that has to do with anything. It would seem that you are comparing stalling speeds when you are landing. I would not have thought that was the ideal way to make a comparison. There are too many variable introduced by doing tests in ground effect and the variations which must be introduced in flying the machine to a safe touchdown. I would suggest comparison should take place at a safe altitude in quiet evening air and the stall should be approached with the application of back stick using the same time/movement frame. Standard measurement exist for this.The mean of a series of tests should give a more accurate picture. I would have expected the addition of a passenger (198 lbs is the accepted standard weight of a crewman here in the UK I believe) to have produced a bigger difference in stall speed. Rule of thumb, I would have flown faster Surely someone on the list can produce the math. Not my forte. It would take me a month Pat ________________________________ Message 7 _____________________________________ Time: 08:58:37 AM PST US Subject: Kolb-List: Re: belt reduction From: "Thumper" Use the 2.6 or more ratio if you can and you will like that Micro-V drive. And 35hp will fly a Firefly quiet well as Jack Harts post prove and did pretty well on the Ultrastar. Wish I had taken a picture of the mounting plate. It was a 30 Minute change out to switch engines which allowed me to do lots of comparative testing. I did a lot of work on an Ultrastar to find a good replacement for the Cuyuna UL-II-02 and I was happy with the 440A BUT it is only 35HP equivalent to the 377 that used to be on a lot of early Firestars. IT is not 40+HP as J-bird or anyone else trying to sell one will state. You can go to the Ultrastar Yahoo group and read the archives about my experiences. The Micro-V worked well, I had the provision crankcase and it mounted right to the engine. I will try to get some pictures attached for you. You do NOT want the 38mm blue cap carb, just use the 32mm VM and it will jet up and run well. I used the Ultra Prop on the Ultrastar for its durability but don't recommend it for the firefly, IVO or wood would be better. And you need to use the Chaparell exhaustt pipe, my weight all up was 80#. I did not have electric start though. Mine ran well and I put 140 hours on it before selling it at Sun-N-Fun 2010. Youtube at thumperfour and you can watch some video at sun and fun. Here is what I posted back then but you can do a search of the Ultrastar Yahoo group and search 440A and read more. I'll try to keep it short. I wanted to get better climb since I am heavy at 225# and I have a BRS installed. History first. The Cuyuna was running well at all of the proper temps and the plane flew well, 300-400fpm climb at around 70 degrees and 400ASL. As the summer was approaching I had heard that the Cuyuna had cooling issues and it was running at 400 CHT already. So I purchased the brand new Kawasaki 440A with a provision crankcase so I could buy the compact Micro-V and have it be a simple bolt in place for the Cuyuna. Goal accomplished. I can swap engines in less than an hour. Starting with the Kaw I bought the 3 blade Ultra prop 54" and an ACS side mounted exhaust so it mounted to the engine like the Cuyuna did. I also ordered it with two prop pulleys, 2.4 and 2.0. That way I could compare the Culver prop to the larger props. With the ACS exhaust it would not spin up the Culver 50x30 prop to about 5800rpm with the 2.0 ratio. Way less than the Cuyuna. I had the same issue with it not spinning up to proper RPM with the suggested pitch blocks on the Ultraprop and the 2.4 ratio. I bought a 54" 2 blade Powerfin and had the same issue. I am only guessing here that it gave me about 30hp with that exhaust. After going to flatter pitch blocks it would fly with the Ultraprop but the climb was very marginal. I then purchased the Chaparell exhaust recommended by the trike guys who fly a lot of the Kaws. Big difference. I had to change pitch settings as now the engine would scream past 7000. After getting the pitch blocks set properly and swapping exhaust back and forth it would show a 600rpm improvement with the Chaparell exhaust. That exhaust is 7# heavier but worth it. Now the Kawasaki weighed exactly the same as the Cuyuna at 80# complete but without any prop. I am guessing 35hp now. But I have yet to reinstall the Culver prop with the 2.0 as an equal test. I was flying and having fun. I plan to do it this month if the weather will settle down. I want to know just what the power of the Kawasaki is. Now the ! advantag es of the Kaw are; lightweight, smoother at idle (same at flying speed) no steel cylinder liners it has all aluminum cylinders with Nikasil coating so it is more forgiving to seisures. The Kaw parts are available at any smowmobile shop. Forget the blue cap carb in the 38mm size it is hard to tune and gains nothing at our RPM. I installed a 32mm and it tunes fine. Now the bad about the Kaw, at the proper 1200 EGT and plug color it runs 430-440CHT on climb, higher than the Cuyuna. I installed the EGT prob where the manual from J-bird recommended 2" from piston skirt. This engine is sensitive to carb jetting in that IF you run it richer to reduce the EGT there is a noticable difference in power. The engine is peaky with this exhaust, there is a certain RPM where then engine will fall off the pipe and a very small increase in throttle and it will hit the pipe. It is managable but keeps me from flying in that rpm range. Best climb is at 1200 EGT and cruise near that and you will get 2.5 to 3 GPH at 50 airspeed. Without the steel liner for the piston I feel safe those 430+ head temps are OK. Try running it richer and you lose performance. I had good luck with J-Bird Jim other than him being long winded and going off on tangents and being stuck in the 80's for oil mix and technology lag. I have run both engines on Castrol TTS synthetic and plan to continue with it. I would have no issues now running the Cuyuna but I would buy the new Micro-V reduction in 2.4 ratio so I can run the larger prop. 2" spacer would be required to lower the engine but would add thrust and keep my climb rate near 500fpm even in the summer. Hope this helps but feel free to call me for more details and opinions. Long winded but hopefully valuable to someone. The Kawasaki is a good alternative to the Cuyuna UL-II-02 but not required. Homer had it right if I just wasn't gravitationaly challenged so much. Dennis More information from testing is now available. I am just passing on some more information I learned today. I re-installed the Culver 50x30 prop with the 2.0 pulley. I was curious what the actual HP of the Kaw 440 is since I have the pipe and carb tuned to 1200EGT on climb like I did the Cuyuna. With the 440A, 32mm Mikuni, Chaparell Exhaust and the Micro-V 2.0 redrive the engine would spin up to exactly the same RPM as the Cuyuna under the same weather conditions. This tells me that any claim to it being 38 or 40 hp is just wishfull thinking. I only have one other test to complete and that is trying the larger 38mm Blue Cap carb. I will try and get around to it this next month. I really don't think it will help as the 32mm passes as much air as this engine can use but? I tried the 38mm carb with the ACS exhaust and that carb was very difficult to tune. Lean spots and bogging. Maybe with this Chaparell exhaust it will be different? Also the "Thrum Thrum" was back just like the Cuyuna had with this two blade prop and the 2.0 reduction. It is annoying more than anything else. BUT the flat spot in the 4600-5300 rpm band was gone. This prop must keep the engine loaded differently than the Ultra Prop. I did not express that in the earlier post but the 2.4 reduction the 54" 3 blade UltraProp had a flat spot, more a feeling of the engine hitting the pipe like on the old motocross bikes. There was a flat spot between 4600 and 5300 that the engine just would not stay in no matter what I did with the jetting. Must be the ultraprop not having twist and it just not loading the engine right at that rpm. It is sensitive to prop loading near this point by climbing or decending. The larger Ultraprop spinning slower DEFINATELY helps the climb rate over the 50" Culver prop but the Culver Cruises at a lower rpm but fuel burn was approximately the same. So your best improvement with a 35hp engine is to somehow increase the prop size to gain thrust. I would love to try a 2 blade Culver set up for the 2.4 reduction, maybe 54x28? Just passing along more information as I learn. Thanks -------- Dennis Long Oakland TN 2001 Kolb Mark IIIC 160+ hours since March 2011 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=366714#366714 Attachments: http://forums.matronics.com//files/100_2537_200.jpg http://forums.matronics.com//files/100_2534_152.jpg http://forums.matronics.com//files/kaw_440_redrive_22_1_micro_v_132.jpg ________________________________ Message 8 _____________________________________ Time: 09:09:31 AM PST US From: "b young" Subject: Kolb-List: stall?????? >I did do stall tests at altitude. 28mph pilot only. Landing straight and level,not diving, just letting that last 3 or 4 ft. >diminish it stalls at 35mph single, 40....2 up. Unless I drop the tail.... then 28mph stall. >The only thing that makes sense is ground effect. >>>>>>>>>>>>>>>>>>>>>>>>>> vic sorry this got longer than I had planned.. but read to the end. maybe it will make sense. and remember the angles and speeds mentioned are only examples, and not accurate numbers. I have to jump on this one,,,, what do you mean by "the above" are you saying when 3 or 4 ft above the runway, and while slowing down when you hit 35mph single, 40....2 up. is when it starts to drop in? and if you drop the tail it wont drop till 28? if I have a clear picture in my minds eye.. then it is not stalling at 35 to 40... when you get to those speeds the amount of lift is decreasing. the faster the wing goes the more lift it can produce at any given angle of attack. examples. at 8 deg angle of attack at 50 a wing may create 1000 pounds of lift, at 60 same wing, same angle of attack it may produce 1100 pounds of lift and at 70 1200 pounds of lift. at 40 maybe 900 pounds of lift. at 30 maybe 800 pounds of lift. so lets say we have a 1000 pound airplane,,, flying at 8 deg angle of attack... at 50 mph it will fly straight and level at any faster speed it will be in a climb . and slower it will be descending because it is no longer producing enough lift to carry the weight. so how do you fly this airplane at 70 mph... you have to fly at 6 deg angle of attack. if at 6 deg angle of attack and 70 mph, the wing produces 1000 pounds of lift it will fly straight and level. lets go the other way. if we fly at 40, in order to get 1000 pounds of lift you may need 11 deg of angle of attack. produces straight and level. no stall. but the tail has to be down more. than at 50 mph. at 30 mph you need 13 deg angle of attack to produce 1000 pounds of lift. straight and level.. no stall at 28 the wing hits the critical angle of attack, (and for example purposes I will say this is 13.5 deg. ) the air over the wing separates and the wing stalls. when this happens the lift drops from 1000 to just above 0. basically you get the parachute value of the wing surface. this is the definition of a stall... so during a landing, you are flying at 50 mph at 8 deg angle of attack, and you start to slow. you will have to keep adding more angle of attack to keep the same lift and you can do this till you reach 28 and 13.5 deg angle of attack.. and at that exact moment, when the angle of attack reaches 13.5, the wing starts to fall through the air and the angle of attack will jump because the plane is no longer going level it is dropping at a 30 deg angle toward the ground,,, added to the 13.5 deg in the wing, the angle of attack is 43.5 deg. and these numbers are progressing as the stall deepens. as you slow further you may be dropping at a 45 deg angle, added to the 13.5 is a 58.5 deg angle of attack. or even more. to get out of a stall, you have to push the nose down, if you are dropping at 45 deg, you have to push over to nearing 45 deg angle, this will do 2 things, (1) the air will reattach to the wing, and (2) you will regain speed. if you pull out gently you have recovered from a stall. if you pull out too hard, you may go into an accelerated stall at an increased g level. so what does all this have to do with stalling at 28 vs 35.. if you are slowing down past 40 to 35 and you do not increase the angle of attack sufficient to maintain the lift to a degree to carry the weight of the plane. the amount of lift goes down, and the plane drops to the ground... it has not stalled. it is controlled descending flight till the wheels bounce on the ground. back to the example if we are at 40 mph and 11 deg angle of attack, 5 feet off the ground,,, and we slow to 35 without increasing angle of attack.. you will start to drop... and if the angle of drop is 5 deg. remember we were at 11 deg angle of attack add to that 5 more degrees due to the drop angle. the wing is now at 16 deg angle of attack... the wing will only go to 13.5. so yes you have stalled the wing at 35. and this would fall under the category of an accelerated stall. and something is going to get bent... if you do it 2 inches off the ground, no problems. and if you are straight and level at 2 inches from the ground and keep pulling on the stick, you can slow to 28 before the angle of attack goes beyond 13.5 and you stall. boyd young ________________________________ Message 9 _____________________________________ Time: 09:26:54 AM PST US From: "vic" Subject: Re: Kolb-List: stall?????? Yes 3 or 4ft above runway. Makes sense now. A rapid descent not a stall. ----- Original Message ----- From: b young To: vic ; kolb-list@matronics.com Sent: Monday, February 20, 2012 12:07 PM Subject: Kolb-List: stall?????? >I did do stall tests at altitude. 28mph pilot only. Landing straight and level,not diving, just letting that last 3 or 4 ft. >diminish it stalls at 35mph single, 40....2 up. Unless I drop the tail.... then 28mph stall. >The only thing that makes sense is ground effect. >>>>>>>>>>>>>>>>>>>>>>>>>> vic sorry this got longer than I had planned.. but read to the end. maybe it will make sense. and remember the angles and speeds mentioned are only examples, and not accurate numbers. I have to jump on this one,,,, what do you mean by "the above" are you saying when 3 or 4 ft above the runway, and while slowing down when you hit 35mph single, 40....2 up. is when it starts to drop in? and if you drop the tail it wont drop till 28? if I have a clear picture in my minds eye.. then it is not stalling at 35 to 40... when you get to those speeds the amount of lift is decreasing. the faster the wing goes the more lift it can produce at any given angle of attack. examples. at 8 deg angle of attack at 50 a wing may create 1000 pounds of lift, at 60 same wing, same angle of attack it may produce 1100 pounds of lift and at 70 1200 pounds of lift. at 40 maybe 900 pounds of lift. at 30 maybe 800 pounds of lift. so lets say we have a 1000 pound airplane,,, flying at 8 deg angle of attack... at 50 mph it will fly straight and level at any faster speed it will be in a climb . and slower it will be descending because it is no longer producing enough lift to carry the weight. so how do you fly this airplane at 70 mph... you have to fly at 6 deg angle of attack. if at 6 deg angle of attack and 70 mph, the wing produces 1000 pounds of lift it will fly straight and level. lets go the other way. if we fly at 40, in order to get 1000 pounds of lift you may need 11 deg of angle of attack. produces straight and level. no stall. but the tail has to be down more. than at 50 mph. at 30 mph you need 13 deg angle of attack to produce 1000 pounds of lift. straight and level.. no stall at 28 the wing hits the critical angle of attack, (and for example purposes I will say this is 13.5 deg. ) the air over the wing separates and the wing stalls. when this happens the lift drops from 1000 to just above 0. basically you get the parachute value of the wing surface. this is the definition of a stall... so during a landing, you are flying at 50 mph at 8 deg angle of attack, and you start to slow. you will have to keep adding more angle of attack to keep the same lift and you can do this till you reach 28 and 13.5 deg angle of attack.. and at that exact moment, when the angle of attack reaches 13.5, the wing starts to fall through the air and the angle of attack will jump because the plane is no longer going level it is dropping at a 30 deg angle toward the ground,,, added to the 13.5 deg in the wing, the angle of attack is 43.5 deg. and these numbers are progressing as the stall deepens. as you slow further you may be dropping at a 45 deg angle, added to the 13.5 is a 58.5 deg angle of attack. or even more. to get out of a stall, you have to push the nose down, if you are dropping at 45 deg, you have to push over to nearing 45 deg angle, this will do 2 things, (1) the air will reattach to the wing, and (2) you will regain speed. if you pull out gently you have recovered from a stall. if you pull out too hard, you may go into an accelerated stall at an increased g level. so what does all this have to do with stalling at 28 vs 35.. if you are slowing down past 40 to 35 and you do not increase the angle of attack sufficient to maintain the lift to a degree to carry the weight of the plane. the amount of lift goes down, and the plane drops to the ground... it has not stalled. it is controlled descending flight till the wheels bounce on the ground. back to the example if we are at 40 mph and 11 deg angle of attack, 5 feet off the ground,,, and we slow to 35 without increasing angle of attack.. you will start to drop... and if the angle of drop is 5 deg. remember we were at 11 deg angle of attack add to that 5 more degrees due to the drop angle. the wing is now at 16 deg angle of attack... the wing will only go to 13.5. so yes you have stalled the wing at 35. and this would fall under the category of an accelerated stall. and something is going to get bent... if you do it 2 inches off the ground, no problems. and if you are straight and level at 2 inches from the ground and keep pulling on the stick, you can slow to 28 before the angle of attack goes beyond 13.5 and you stall. boyd young ________________________________ Message 10 ____________________________________ Time: 11:00:43 AM PST US Subject: Kolb-List: Re: belt reduction From: "Ducati SS" Dennis - thanks for the info - thats more than I have been able to find in a month of poking around the internet. I have a number of options to explore. Along with the Firefly I have a CGS Hawk. The Hawk was licensed with a 440A so I may just mount the new Kawasaki on that and hope something better comes along in the future. The whole point of the swap is to save weight so if the TA is not at least 6 to 8lbs. lighter, its not worth the effort. I weigh less than 170 so the plane performs well, however my strip has only 1 good approach and if I have to go around I need alot of climb. Perhaps my fears about the MZ will prove to be a non issue and I will buy one of those for the Firefly. Another thought is that my 447 only has 13hrs. so I am in no real hurry, I may build a test stand and experiment with the TA. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=366726#366726 ________________________________ Message 11 ____________________________________ Time: 11:29:35 AM PST US From: "Pat Ladd" Subject: Re: Kolb-List: Kolb quit revealed Unless I drop the tail.... then 28mph stall.>> I do not understand how you CANNOT be dropping the tail. If you are trying to stall you must either cut the power and try to keep her flying by raising the nose, which drops the tail or You are keeping the same power setting and losing speed by climbing, which drop the tail. If you are not doing one of those two things how are you getting back to stalling speed? Or am I just thick (which is more than possible) Pat ________________________________ Message 12 ____________________________________ Time: 02:54:26 PM PST US From: chris davis Subject: Kolb-List: rotax377 KOLBERS, I am in search of an engine to replace the 447 the Firefly was des igned for that doesnt cost $5000 I was looking at 377s for sale did google search and ended up at Ski Do sites on Ebay and Craigslist -ETC They are selling ski do's with 377s some with electric start for $250 to $450 ! are these the same cases that the aircraft 377s come in? will a reduction gear bolt on to them?If they are and need to be rebuilt they will still be a lot cheaper than the $5000 engines I have been looking at like the MZ-201 !Any input will be appreciated. Chris=0A=0A=0AChris Davis=0AKXP 503 492 hrs=0AG lider Pilot=0ADisabled from crash building Firefly ________________________________ Message 13 ____________________________________ Time: 03:03:57 PM PST US From: chris davis Subject: Kolb-List: NI-CAD Kolbers , I forgot to ask in- my last post asking about the 377s , Do the NI-CAD batteries the light ones, have enough power to start a ROTAX 377- 4 47 ? Has anyone tried one? Thanks Chris=0A=0A=0AChris Davis=0AKXP 503 492 h rs=0AGlider Pilot=0ADisabled from crash building Firefly ________________________________ Message 14 ____________________________________ Time: 03:23:38 PM PST US From: Herb Gayheart Subject: Re: Kolb-List: NI-CAD Chris A fairly small motor cycle battery works.. ES14L-A2 from Wally ... My buddy who died last May used it to start his 447... By the way...I may sell his 447... New From SMLA in 2010... Has 13 hours...I have the Bill of Sale from them.. After market GPL electric start...Heads torqued after 1 hour... One of the last "new" 447's... from what I hear... $4499 .00 when he bought it in June of 2010... B Box 2.58 to 1... Herb At 05:01 PM 2/20/2012, you wrote: >Kolbers , I forgot to ask in my last post asking about the 377s , >Do the NI-CAD batteries the light ones, have enough power to start a >ROTAX 377- 447 ? Has anyone tried one? Thanks Chris > >Chris Davis >KXP 503 492 hrs >Glider Pilot >Disabled from crash building Firefly > ________________________________ Message 15 ____________________________________ Time: 04:29:58 PM PST US From: Charlie England Subject: Re: Kolb-List: NI-CAD On 02/20/2012 05:01 PM, chris davis wrote: > Kolbers , I forgot to ask in my last post asking about the 377s , Do > the NI-CAD batteries the light ones,have enough power to start a ROTAX > 377- 447 ? Has anyone tried one? Thanks Chris > Chris Davis > KXP 503 492 hrs > Glider Pilot > Disabled from crash building Firefly Hi Chris, I think you're looking for 'SLA' (sealed lead acid) or 'VR-RG' (valve regulated recombinant gas) batteries (same thing, different names). There were a few NI-CAD batteries certified for 'big iron' a/c, but there's a history of fires with them, too. SLA batteries have pretty much taken over the market for larger high current batteries used in everything from computer backup power supplies to powered wheel chairs to starting batteries for motorcycles & watercraft. SLA batteries use the same charging technology as old flooded cell batteries, don't leak, can be installed in any position, & aren't prone to thermal self destruction like the big ni-cads were. An SLA battery that weighs about 12-14 lbs (about 1/2 the size of a lawn tractor battery) will easily start a 360 cu in a/c engine. When you start looking, look for ones intended as starting batteries. The ones made for computer backup and wheel chairs don't have quite as much short term 'grunt' for starting, & won't last quite as long if used to start a motor. (Though anything over about 10 ampere-hours would probably work on a small motor like a 337.) Charlie ________________________________ Message 16 ____________________________________ Time: 05:13:51 PM PST US Subject: Kolb-List: M3c first flight, no kolb quit From: "awcbs" Got my First flight this evening in a kolb. nicest eve here in western Pa for months, so I figured it was a good time for me and the old girl. had been doing some crow hops at the end of of the year, and a few this year. She was running good, so couple hops this evening and we decided to go for it. Had a little private discussion between us and asked her not to kolb quit. Well she didn't and I didn't and were both very happy. Sorry couldn't help it, all this kolb quit talk had me a little worried. this was my first flight in the kolb m3, or any kolb for that matter. bought her as a project, fixed her up at the end of the year, put on a 503. I know it isn't the most powerfull eng choice, but it's what I had. She flew good, and didn't have any bad habits. I was a little worried thou with all the talk on here, flew the aproach at 60 no flaps, . I think she's an easy flyer, lands very easy also. I'm a low time ul guy, compared to some. only had time for a couple trips around the pattern. couple take offs and landings. can't wait for the next nice day here to put some time in her. looking for a decent deal on a 582 for her if anyone knows of one. thanks AJ -------- AJ Waldor MK3C 503 Phantom 503 Rans S-9 Chaos 503 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=366772#366772 Attachments: http://forums.matronics.com//files/aj_234_937.jpg ________________________________ Message 17 ____________________________________ Time: 05:20:18 PM PST US From: Dana Hague Subject: Re: Kolb-List: rotax377 At 05:53 PM 2/20/2012, chris davis wrote: >KOLBERS, I am in search of an engine to replace the 447 the Firefly was >designed for that doesnt cost $5000 I was looking at 377s for sale did >google search and ended up at Ski Do sites on Ebay and Craigslist ETC >They are selling ski do's with 377s some with electric start for $250 to >$450 ! are these the same cases that the aircraft 377s come in? will a >reduction gear bolt on to them?If they are and need to be rebuilt they >will still be a lot cheaper than the $5000 engines I have been looking at >like the MZ-201 !Any input will be appreciated. How about a Cuyuna? 35HP, They go for a lot less than a Rotax, parts are cheap, and IMHO their bad reputation is largely undeserved. -Dana -- Giving money and power to government is like giving whiskey and car keys to teenage boys. ________________________________ Message 18 ____________________________________ Time: 06:36:11 PM PST US Subject: Re: Kolb-List: M3c first flight, no kolb quit From: kinne russ Good for you, A J! -- have many more pleasant flites in your Kolb; you've earned them. Russ K do not archive On Feb 20, 2012, at 8:13 PM, awcbs wrote: > > Got my First flight this evening in a kolb. nicest eve here in western Pa for months, so I figured it was a good time for me and the old girl. had been doing some crow hops at the end of of the year, and a few this year. She was running good, so couple hops this evening and we decided to go for it. > Had a little private discussion between us and asked her not to kolb quit. Well she didn't and I didn't and were both very happy. > > Sorry couldn't help it, all this kolb quit talk had me a little worried. this was my first flight in the kolb m3, or any kolb for that matter. bought her as a project, fixed her up at the end of the year, put on a 503. I know it isn't the most powerfull eng choice, but it's what I had. She flew good, and didn't have any bad habits. I was a little > worried thou with all the talk on here, flew the aproach at 60 no flaps, . I think she's an easy flyer, lands very easy also. > I'm a low time ul guy, compared to some. only had time for a couple trips around the pattern. couple take offs and landings. can't wait for the next nice day here to put some time in her. looking for a decent deal on a 582 for her if anyone knows of one. thanks AJ > > -------- > AJ Waldor > MK3C 503 > Phantom 503 > Rans S-9 Chaos 503 > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=366772#366772 > > > > > Attachments: > > http://forums.matronics.com//files/aj_234_937.jpg > > > > > > > ________________________________ Message 19 ____________________________________ Time: 07:33:30 PM PST US From: "Jack B. Hart" Subject: Kolb-List: NI-CAD From: chris davis > Kolbers , I forgot to ask in my last post asking about the 377s , Do the NI-CAD batteries the light ones, have enough power to start a ROTAX 377- 447 ? Has anyone tried one? > Chris, I have been using an UltraStart Red Battery. They are quite expensive but very light. You can view the battery and the holder that I used at: http://jackbhart.com/firefly/firefly142.html The first battery did very well, but I was disappointed with the second, in that, it did not last very long. I popped the top red part off the battery and discovered the actual battery model number. The cost of this original unmodified battery is about one quarter of the UltraStart Red. I was able to purchase a replacement battery at a local shop and add the original heavy terminals to the new battery. How it was done can be seen at: http://jackbhart.com/firefly/firefly160.html I have been working on a LiFepo4 battery. I havew four A123 cells mounted and the terminal connections welded. I believe it will shave another pound or so off the FireFly, but it has to wait until I get FireFly back in the air this coming Spring. I hope this helps. Jack B. Hart FF004 Winchester, IN ________________________________ Message 20 ____________________________________ Time: 08:29:03 PM PST US From: "John Hauck" Subject: RE: Kolb-List: M3c first flight, no Kolb quit Got my First flight this evening in a Kolb -------- AJ Waldor Ain't nuthin' like it. Congratulations. john h mkIII Titus, Alabama ________________________________ Message 21 ____________________________________ Time: 08:52:50 PM PST US From: chris davis Subject: Re: Kolb-List: rotax377 Thanks Dana I will look into it . do you know anything about the ski do rot ax 377s ? =0A=0A=0AChris Davis=0AKXP 503 492 hrs=0AGlider Pilot=0ADisabled from crash building Firefly=0A=0A=0A________________________________=0AFrom : Dana Hague =0ATo: kolb-list@matronics.com =0ASent: Monday, February 20, 2012 8:18 PM=0ASubject: Re: Kolb-List: rotax377=0A=0A =0AAt 05:53 PM 2/20/2012, chris davis wrote:=0A=0AKOLBERS, I am in search o f an engine to replace the 447 the Firefly was designed for that doesnt cos t $5000 I was looking at 377s for sale did google search and ended up at Sk i Do sites on Ebay and Craigslist- ETC They are selling ski do's with 377 s some with electric start for $250 to $450 ! are these the same cases that the aircraft 377s come in? will a reduction gear bolt on to them?If they a re and need to be rebuilt they will still be a lot cheaper than the $5000 e ngines I have been looking at like the MZ-201 !Any input will be appreciate d. =0AHow about a Cuyuna?- 35HP, They go for a lot less than a Rotax, par ts are cheap, and IMHO their bad reputation is largely undeserved.=0A=0A-Da na=0A=0A=0A=0A=0A--=0AGiving money and power to government is like giving w == ________________________________ Message 22 ____________________________________ Time: 09:00:01 PM PST US From: chris davis Subject: Re: Kolb-List: NI-CAD Jack Thanks alot for the email o- the batteries I looked for the data. It is a Portalac PX12050SHR and distributed by GS Battery. Internet replaceme nt batteries can be purchased I got a price of $14 for a 4.5 ib 12volt batt ery very nice .-- thanks again Chris=0Ap.s. do you know anything about the SkiDo 377s ?=0A-=0A-=0AChris Davis=0AKXP 503 492 hrs=0AGlider Pilot =0ADisabled from crash building Firefly=0A=0A=0A___________________________ _____=0AFrom: Jack B. Hart =0ATo: kolb-list@matron ics.com =0ASent: Monday, February 20, 2012 10:37 PM=0ASubject: Kolb-List: N rnet.net>=0A=0ADate: Mon, 20 Feb 2012 15:01:23 -0800 (PST)=0AFrom: chris da vis =0A>=0AKolbers , I forgot to ask in- my last pos t asking about the 377s , Do the =0ANI-CAD batteries the light ones, have e nough power to start a ROTAX 377- 447 =0A? Has anyone tried one? =0A>=0A=0A Chris,=0A=0AI have been using an UltraStart Red Battery.- They are quite expensive but =0Avery light.- You can view the battery and the holder tha t I used at: =0A=0Ahttp://jackbhart.com/firefly/firefly142.html=0A=0AThe fi rst battery did very well, but I was disappointed with the second, in =0Ath at, it did not last very long.- I popped the top red part off the battery =0Aand discovered the actual battery model number.- The cost of this ori ginal =0Aunmodified battery is about one quarter of the UltraStart Red.- I was able =0Ato purchase a replacement battery at a local shop and add the original heavy =0Aterminals to the new battery.- How it was done can be seen at:=0A=0Ahttp://jackbhart.com/firefly/firefly160.html=0A=0AI have been working on a LiFepo4 battery.- I havew four- A123 cells mounted =0Aand the terminal connections welded.- I believe it will shave another pound =0Aor so off the FireFly, but it has to wait until I get FireFly back in th e =0Aair this coming Spring.=0A=0AI hope this helps.=0A=0AJack B. 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