Matronics Email Lists :: View topic - Flutter / Firestar Test Flight #2

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Flutter / Firestar Test Flight #2
Goto page 1, 2 Next

Matronics Email Lists Forum Index -> Kolb-List

View previous topic :: View next topic

Author Message

victorbravo(at)sbcglobal.
Guest

Posted: Thu Aug 09, 2018 9:15 am Post subject: Flutter / Firestar Test Flight #2

Please let me clarify my comment so it does not accidentally cause a safety issue for someone. I believe that adding weight forward of the hinge line works against flutter. BUT I did NOT mean to imply that spades would replace or equal the Kolb tip weights. Those are there for a reason, as many of you know from experience. Flutter would scare the s*** out of me in a Kolb or any other aircraft. 



Test Flight Report for flight #2 



I flew my Firestar again yesterday morning for about 20-25 minutes. I was a little more confident in everything, so I took it right up to 1500 feet above the airport and flew several laps above the runway. 



The aircraft needed a few pounds of forward pressure on the stick, as I have described before. However, this was at an indicated airspeed of only 45 miles per hour. A lot slower than one would expect for a properly rigged aircraft. I realized at this point that I needed to raise the leading edge of the stabilizer as a couple of people have mentioned. A "trim tab" for this would have been pretty large and bent pretty far.



Also on the test flight, I paid specific attention to the rudder trim. The aircraft required five or six pounds (guess) of LEFT rudder in level flight, again at the 40-45 mile an hour speeds I was flying. It also needs left rudder on takeoff to keep it straight. This was very surprising to me because the propeller turns the "conventional" direction, meaning that it is turning the same direction as a Cessna or J-3 Cub, where you need right rudder on takeoff. The torque from the engine, especially with a high ratio gearbox and a big wide propeller, SHOULD be trying to roll and yaw the aircraft to the left, requiring right rudder. But this is the opposite of how it was in flight.



I briefly let off of the rudder pressure and the airplane yawed to the right significantly. The air flow direction and the view from the seat verified this without a doubt... so it does not seem that this problem could be caused by the rudder pedals not being adjusted well.



So I have a QUESTION for the experienced Kolb builders/owners here: Dies the stock Kolb engine mount have a thrust offset angle built into it??? The way this aircraft is behaving would be explained by the Kolb fuselage having several degrees of RIGHT thrust built into the engine mounts. Perhaps this would have been done to compensate for engines that turn the other direction . I'm having trouble understanding how an engine that turns a "right hand" propeller is making it steer to the RIGHT instead of left.



One other thing I tried in flight was to slow the aircraft down. This seems pretty funny starting from 40 and 45 miles an hour, but I had plenty of altitude. With the vortex generators installed, and having read the flight reports from several other Kolb owners, I fully expected the aircraft to stall at 30 MPH. But as I slowed down to 35 MPH it gently stalled. I repeated this again after speeding back up to 40, to make sure I had actually stalled it the first time. Once again at 35 indicated, it provided a fairly gentle stall. No significant buffeting or shaking before the break, but a pretty gentle straight-ahead stall with the nose dropping 20 degrees when it did let go.



This was disappointing, since I installed the VG's specifically to get the lower stall speed they usually provide. To be honest, I was pretty disappointed, since the old Taylorcrafts and J-3 Cubs stall just under 40 MPH, and a big part of the reason I wanted an ultralight style aircraft was to fly really slow into really short landings. 



The last thing I tried to pay specific attention to was the heavy ailerons getting better at lower speeds. But again on this flight my speeds were already slow..I moved the stick left and right and it has adequate roll control, but the stick forces were far far higher than the elevator or rudder forces, and this was again at only 40 and 45 indicated. Looking out at the ailerons as I moved them, they were deflecting equally along their length... meaning that the outboard tip of the aileron waas moving as much as the inboard end of the ailerons were moving. The ailerons were not "twisting" very much. Since I am not yet familiar with the Kolb I was not able to assess whether the amount of aileron movement in flight was the same as it was on the ground (with the same amount of stick movement).



I realized that I had taken too much pitch out of the propeller. The engine RPM was 5200-5300 when I was flying around at 40-45 miles an hour, and I specifically wanted to be in the "cruising" RPM range instead of maximum continuous power (which is 5800). So I will probably put two degrees more pitch into the propeller before the next test flight.



After the flight I spent the rest of the day making and installing the parts to raise the leading edge of the tail. I raised the leading edge of the tail by 3/4 of an inch. using short steel extension plates.



Again, my most important question for Kolbers is whether the Kolb Firestar 2 fuselage is known to have tight hand thrust offset built into the welded engine mount. Only this would explain why an engine that should be pulling the airplane left would actually be pulling it right.



Bill Berle

www.ezflaphandle.com  - safety & performance upgrade for light aircraft

www.grantstar.net           - winning proposals for non-profit and for-profit entities



--------------------------------------------

On Thu, 8/9/18, John Hauck <jhauck(at)elmore.rr.com> wrote:



 Subject: RE: Firestar/HKS First Flight

 To: kolb-list(at)matronics.com

 Date: Thursday, August 9, 2018, 5:10 AM

 

 

 Hauck" <jhauck(at)elmore.rr.com>

 

 True. Some.  But not enough to get

 the job done, unless additional weight is added to equal the

 out of balance aileron.

 

 When I originally built my MKIII,

 before Kolb admitted there might be a problem with aileron

 flutter, I fabricated some really neat counter balance

 weights and attached them, very securely to 6061 plates I

 fixed to the inboard end of each aileron.  First couple

 flights went well during testing.  Then, entering the

 traffic pattern at my local airport, the MKIII went into

 violent flutter.  Snatched the stick right out of my

 hand.  Chopping power and corralling the stick as far

 back as I could get it, gets it out of flutter.  I had

 learned that exercise early on with my US and FS, but Kolb

 wasn't buying it.  Landed and promptly removed my

 beautiful counter balance weights.

 

 Right about 85 mph, where the airplane

 and I liked to cruise was right on the edge of

 flutter.  Turbulence would set it off quickly.  I

 flew the MKIII in this condition to Sun and Fun 1993, to

 Homer's to paint the Lasers, and then to Oshkosh.  At

 Oshkosh I had to fly a photo shoot with a Cessna 208. 

 He was having trouble slowing to 85 and I was going into

 flutter at 85.  It was a tough flight, but we got'er

 done.

 

 I was getting ready to do my flight

 around CONUS and up to Alaska, wondering how I was going to

 make it with the flutter problem.  I dreamed up all

 kinds of cures to keep the aileron control linkage as tight

 as possible, but I was still susceptible to flutter.  

 

 Finally, the next year at Sun and Fun

 Dick Rahill got the factory FS into severe flutter.  He

 was white as a ghost and visibly shaken when he finally got

 on the ground after flying from Lakeland South to the UL

 strip on the edge of a severe thunderstorm.  A week

 later I got a set of FS aileron counter balance weights from

 Kolb, made them fit my MKIII, and never again experienced

 aileron flutter.  It was wonderful and I was a month

 from beginning my big flight of 1994.  I had been

 flying with flutter for 10 years by this time.

 

 Don't know why my design didn't work,

 but Kolb's did.

 

 My design was ahead of the hinge line

 with bullet shaped weights like I had seen on other

 aircraft.  Guess I stuck them on the wrong end of the

 aileron because they aggravated the situation.

 

 john h

 mkIII

 Titus, Alabama

 

 

 

 

 --

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu Aug 09, 2018 10:26 am Post subject: Flutter / Firestar Test Flight #2

There is in offset in the engine mount on any standard Kolb.



I spent a lot of time and effort experimenting with engine off set to correct trim my perceived trim problems in my FS.  All was for naught.  Best left just like Homer Kolb designed.



I did the same with the leading edge of the upper vertical stabilizer.  Again, a waste of time.  Best left centered like indicated on the plan sheet.



Brother Jim fabricated the first pair of adjustable forward horizontal stabilizer mounts.  Had 3 choices of angle.  I flew off most of the 40 hours on the original factory MKIII.  I knew what we needed to make my  MKIII right.  Same for moving the main gear forward, and many other modifications that were all blessed by Homer Kolb the morning after we would make them the night before.  Many of our mods were incorporated in subsequent MKIII airframes and other Kolb models from changes we made to mine, SN:  M3-11.  When I got to Homer's first of Jan 1991, 10 air frames had been fabricated.  Brother Jim had gotten to Homer's around the first of Dec 1990, the help out with some welding, when both Homer's welders were laid up with health problems.  I experimented with all three positions, but the center position was where the aircraft settled down and felt comfortable.  The other two positions made the MKIII feel like it was riding on a ball.  Keep wanting to fall off in all different directions.  Not fun to fly.



We cured the adverse yaw problem after many hours and a 17,200 mile flight.  On that flight I flew a half ball out of trim the entire way.  I'm still a half ball out of trim, but the MKIII flies straight and level by doubling the size of the rudder trim tab.  The prop wash comes off the engine twisting, hits the left side of the vertical stabilizer and the top of the left horizontal stabilizer.  This is verified by crank case ventilation depositing oil and fuel spray on those surfaces and no place else.



It is normal to have the aircraft want to drop the nose before some form of pitch trim is installed.  Primarily because it is a high mounted pusher.  Looks like Berle's Kolb could have raised the engine to run a longer prop.  However, there is something that needs to be tweaked to get the aircraft to fly level.  A few ways to do it:  1-forced trim, 2-elevator trim tab, and horizontal stabilizer.  On a FS I'd go with an elevator trim tab which is adjustable, simple, and easy to install.  Doesn't take a lot of trim tab to get the job done, and if it does it is a good way to correct a pitch problem.  However, adverse pitch trim up ain't normal and should be thoroughly investigated.



Has your ASI been calibrated?  Most are not very accurate at slow speeds.  I fly out and back on reverse headings at a constant airspeed, add them together and divide by 2 to get ASI error.  May or may not help at very slow speeds.  You can also use a GPS, which is ground speed only, on a calm day, to get a pretty good idea of ASI calibration.  You should be at 30 or lower before stall.  My MKIII will easily hit 30, sometimes less.



Because a Cub and your engine turn the same way does not mean that the aircraft response will be the same.  One's a tractor and one's a pusher, IMHO.



Ailerons move very little in flight to get the results you are looking for.  They are oversized.  I reduced the area of my ailerons when I built my MKIII knowing I had a lot more aileron than I needed.  Homer designed his aircraft primarily for safe, very slow flight, to be able to stay in contact with what was happening in the trees and on the ground he was flying over.  Cut the aileron cord in half and you may get the results you are looking for.



I believe adverse yaw is caused by prop wash primarily.  A rudder trim tab corrects that problem.



With less than an hour's flight time, if it was me, I'd get out there and learn how to fly the aircraft before I decided to change anything unless it was absolutely unsafe to fly in that condition.  It takes some hours to learn your Kolb.  Especially in your case where you came from GA.  I came from helicopters and had no problem flying Kolbs.  To me, they were a lot like rotary wing.



Wow!  My mind has a severe case of diarrhea, but the above are my thoughts on the situation.



john h

Titus, Alabama

  



--

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

stuart(at)harnerfarm.net
Guest

Posted: Thu Aug 09, 2018 10:27 am Post subject: Flutter / Firestar Test Flight #2

Hi Bill,



Good to hear about your safe and successful 2nd. Flight.



First question: Do you know your ASI is accurate? You can get a speedometer (GPS based) app for your phone and do a straight path for a couple of miles, then repeat the other direction for a quick and dirty check. Won't be perfect but is good for a quick verification.



Next, yes to the clockwise prop and left rudder. My Firefly does exactly the same thing. P-factor should cause it to turn left but it does not. We had quite a discussion about this back after my first flights. Short version of the conclusion is that prop wash hitting the right side of the vertical stabilizer is more powerful than P-factor and easily overrides it. I have confirmed this by observing the tail while warming up the engine. Dead bugs collect on the right side of the vertical and the rudder deflects to the left. The pusher configuration with a low boom tube presents no resistance between the prop and the tail unlike something more conventional that has all that covered fuselage to "straighten out" the airflow between prop and tail.



Advice (on par with the price of it): Don't go messing with the tail until you get the proper cruise set up with RPM/Pitch and confirm the ASI. Also, don't change more than one thing at a time between flights. You can easily confuse yourself and muddy the results by trying two things at once, no matter how un-related they seem. Been there, done that. 



Question two: How was the elevator pressure during the stalls, descent and climb out compared to "cruise"?



You're doing great! Keep it up.



Stuart



--

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu Aug 09, 2018 10:45 am Post subject: Flutter / Firestar Test Flight #2

First sentence should have read, "There is no offset in the engine mount on standard Kolb aircraft".  Sorry about that.  I even proof read this one a couple times.  I'll blame that on age.  



john h

mkIII

Titus, Alabama

--

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu Aug 09, 2018 10:48 am Post subject: Flutter / Firestar Test Flight #2

Kolbs produce negligible P-factor.  Can't remember where I got that tidbit.  Yaw problems on takeoff are probably prop wash on the tail section, as you mentioned.



john h

mkIII

Titus, Alabama





--

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

victorbravo(at)sbcglobal.
Guest

Posted: Thu Aug 09, 2018 11:51 am Post subject: Flutter / Firestar Test Flight #2

First sentence should have read, "There is no offset in the engine mount on standard Kolb aircraft".  



Thank you for that information, that allows me to eliminate one possible cause. I was really hoping that I didn't have to make another offset engine mount plate to straighten out a built-in offset..



The explanation about the air swirling around from the prop and hitting one side of the tail more than the other makes sense to me, I can see that as being a possibility. What I have to do in order to verify that is to make a power-off glide. My model airplane experience tells me that if it glides straight then it's an engine thrust offset problem, and if it needs the rudder in the glide then it's some kind of an airframe construction/damage/repair/warp issue.



To answer a question that was raised about the elevator force during the stall, it was almost the same as in level flight. I allowed the speed to drop off very slowly, so I was holding the same amount of pressure, maybe just a tiny little bit less, in order to reach stall speed. I can 100% say that I did not have to "pull" the stick back to stall it like you have to do on a C-172. What I did was the exact opposite of the dramatic exaggerated "airshow" stall where you make the airplane rear up like a horse and then stop in mid-air. This was a level flight textbook stall.



If I am remembering correctly, I believe it was Rex and Richard who mentioned they had successfully raised the front of the stabilizer to re-rig the pitch on the aircraft. I think it was Richard's EXCELLENT "Old Poops" website that I researched on this as well (THANK YOU for this website).The figure of 7/8 of an inch was mentioned, and I purposely went just a little less than that to be conservative. I have reasonably high confidence that the aircarft will still be very controllable with this change. The Cessna 180 / 182 and the Piper fabric aircraft all use the leading edge of the stabilizer for pitch trim, and the stabilizer travels far more than 3/4 of an inch. But I'll make sure I am paying attention during the takeoff roll to see if it is trying to nose over. If it is doing that excessively I will abort the takeoff roll.



John H mentioned reducing the chord of the ailerons. I would try to not have to do that, because it creates the possibility of not having enough control in an emergency. After all the discussion about the Kolb's heavy ailerons, and having read a lot about it by now, my question is why are the ailerons still heavy at very low speeds? I understand 100% that the big ailerons will tend to get difficult at 70-80 MPH, and that it is just part of the design. Got that loud and clear. 



But several experienced Kolbers have said that slowing the airplane down will make most of this problem go away. My Firestar ailerons are not as heavy as Jimmy O'Neal's Mark 3 was, but they are still somewhat heavy, even down at 40 MPH.



Once again, thanks to everyone for taking time and energy to participate in this discussion and offer their opinion/experience.

 

 Bill Berle

Los Angeles

 

 

 

 

 --

gdhelton(at)gmail.com
Guest

Posted: Thu Aug 09, 2018 12:23 pm Post subject: Flutter / Firestar Test Flight #2

Well guys, we have sure beaten this thread to death.

And this I hope this will be the last of my input. 

Bill, you are are GA/ Sailplane Pilot. You’ve now entered the world of flying an all new category of flight. You have developed some habits that will not serve you well in ultralight type aircraft. As a former ultralight instructor I can say with confidence that the worst times were spent converting GA pilots to UL pilots because, “They already knew how to fly.”

That being said, you’re not flying a “1400lb spam can” anymore. You’re a butterfly or hummingbird. You need a new mind set. Every little change in wind direction, wind speed, thermals, hills and tree lines will change what’s going on inflight. Ultralights are not aileron controlled aircraft. They are primarily rudder, elevator and throttle. You know how to control speed. Stick forward, fast. Stick back, slow. Throttle forward,up. Throttle back, down.  Rudder  is everything, learn to have busy feet. Takeoff, cruise and decent. Think feet, feet, feet... you cannot let you feet get lazy in an ultralight.That’s from the time you taxi to the time you park at the end of the flight. If the nose goes right on takeoff, push the left pedal. If your nose is lifting at cruise push it down and you might want to adjust you throttle a bit. Find your best climb speed and use it. Find your decent or guide speed and use it. Learn to feed your throttle in slowly on takeoff and reduce it slowly upon approach. Fly the friggin’ plane. You’re in charge.

Fly it all the way to the ground and then keep flying it. 

Stop Engineering and go out and enjoy the airplane you’ve worked so hard at completing. Your Firestar will never fly like my Firestar or John’s MKIII. Learn to fly an ULTRALIGHT. Learn your airplane, and learn to fly it well. Get 50 hours in the air and on the ground in it and then maybe we might change some things. Flying is easy! It’s landing and all the stuff on the ground that will screw ya up. Love ya man, go flying. 



George H.

Firestar, FS100, 2702 Hirth 

14GDH

Mesick, Michigan 

gdhelton(at)gmail.com



Sent from my iPhone



[quote] On Aug 9, 2018, at 2:48 PM, John Hauck <jhauck(at)elmore.rr.com> wrote:

 

 

 

 Kolbs produce negligible P-factor.  Can't remember where I got that tidbit.  Yaw problems on takeoff are probably prop wash on the tail section, as you mentioned.

 

 john h

 mkIII

 Titus, Alabama

 

 

 

 

 --

stuart(at)harnerfarm.net
Guest

Posted: Thu Aug 09, 2018 12:26 pm Post subject: Flutter / Firestar Test Flight #2

Bill,



I may have missed it, but where is the CG with pilot and full fuel? What you are describing sounds almost like a tail heavy condition. Trying to trim out an aft CG would not be a good thing.



Do you see significant elevator force changes with changes in power?



Stuart



--

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu Aug 09, 2018 12:51 pm Post subject: Flutter / Firestar Test Flight #2

If you have a 60 to 80 or more mph wind blowing on the side of the rudder and vertical stab, on a Kolb, it will turn the aircraft.  In small increments I started out with 3/4" offset of forward edge of the upper vertical stabilizer and ended up with 1 1/4" offset.  The effect was negligible.  The rudder trim tab, a large one, fixed the problem.  Screwing with the vertical stab was a waste of time, but was the only way to find out if it would work.  I tried to get Kolb to punch a lot of extra holes in the tail boom, but they never got around to it.  I think New Kolb may have put that change in the plans for a MKIIIx, but didn't keep it there long.



More than several folks have gotten into a mush stall in a Kolb, never realizing this, until it hit the ground.  Completely controllable, but it would not climb or maintain altitude.  Years ago I calculated the rate of decent in feet per minute when the Kolb was in a mush.  I don't remember all the numbers, but it was very, very close to the rate of decent of a T-10 parachute, 18 feet a second, that we jumped back in the 1950 and 60s.  At that rate you shouldn't get hurt, but the aircraft will.  That was for my FS.  Never computed for my MKIII.



Stalls in Kolbs are nonevents unless very close to the ground.  Then you will get hurt, as will your aircraft.  In order to make a classic stall you have to pull the nose up and hold the stick back to make it look like you really stalled, like Bill B said.



Kolbs will spin.  My FS with engine at idle, controls crossed up and locked, would not do a full turn before it flew out of the stall with the controls still crossed up.  I was doing aerobatics at the Ultralight Flight Farm, Monterey, NY, in 1989, with my FS.  I was able to do power off loops.  Start out at 8,000 feet over the farm, nose straight down, when it hit 90 mph, I initiated the loop.  Got to where I could do two or three loops before I ran out of altitude and land.  I could not restart the 447 by hand after it cooled off which only took a couple minutes during glide.  I was messing around engine off one day, and decided to try an engine off stall.  Went right into it and the FS spun up like a top.  I think this had something to do with that big disc when the engine was at idle.  Needless to say, I was very surprised.  I've gotten into a lot of arguments about the difference in drag with engine at idle and dead stick.  Some folks say there is none.  I know better, and it is easy to demonstrate.



Where were we?



Your ailerons are still heavy at slow speeds because they are huge compared to what is really required for safe flight.  Plus...it's a Kolb.  



Jimmy O's MKIII was the result of someone changing the geometry of the aileron control system.  The original owner had a terrible time contending with that problem.  Sometimes, most of the time, it is not wise to try to reengineer a designer's work.



john h

mkIII

Titus, Alabama



--

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu Aug 09, 2018 1:35 pm Post subject: Flutter / Firestar Test Flight #2

I can't speak for other ULs, only Kolbs and a couple flights in the Howland Honey Bee (too many years ago to remember all its flight characteristics).  IMHO Kolbs are not rudder airplanes, based on my own flying experience with them.  I've found that the Kolbs are more aileron aircraft, with a little rudder to keep them trimmed, and of course more rudder on takeoff, landing, and taxiing.  Maybe I'm different because I still have a lot of rotary wing stuck in my head after all these years.  I don't know.



Once the Kolb is trimmed up in yaw, I can put my feet on the deck, and fly the Kolb with aileron and elevator, trim ball centered, making coordinated turns.  The aileron geometry is really good on Kolbs.  Homer got that right.



That's my experience and I am sticking to it.  I can't speak for other ULs because I have only flown one other UL other than Kolbs, Burt Howland's little biplane, the Honey Bee.  It was a little doll baby.  Burt and Ellen Howland, rest in peace my friends, attended The Ultralight Flight Farm in NY, 1988-89, where I met them.  They were a lot of fun.  I didn't ask, but Burt offered me the chance to fly his classic looking little bird.  Landing was a no brainer.  Set it up on final at 25 mph, hold that attitude, and a tiny flare, it's on the ground.  I can't remember if the Honey Bee was a rudder plane or not.  Been too long ago.  Certainly wasn't an Aeronca Champ.  



john h

mkIII

Titus, Alabama

--

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

zeprep251(at)aol.com
Guest

Posted: Thu Aug 09, 2018 1:47 pm Post subject: Flutter / Firestar Test Flight #2

Bill ,don’t be too sure about stall speeds until you can authenticate your airspeed indicator.your prop create a swirl like a screw that twists around the fuselage and that blast of air hits the side of the vertical and moves it.I think the mounts are straight.the vg’s are doing their job, no sharp unexpected drop,I raised the horizontal on my FS2 and still had to add some weight in the nose to make it feel good. If I weighed 200# it would have been better .Kolbs need to be a little closer to the forward end of the CG to feel right in my opinion.I put heavier springs on pedals to stop the oscillations caused by the prop.



[quote] On Aug 9, 2018, at 1:15 PM, Bill Berle <victorbravo(at)sbcglobal.net> wrote:

 

 

 

 Please let me clarify my comment so it does not accidentally cause a safety issue for someone. I believe that adding weight forward of the hinge line works against flutter. BUT I did NOT mean to imply that spades would replace or equal the Kolb tip weights. Those are there for a reason, as many of you know from experience. Flutter would scare the s*** out of me in a Kolb or any other aircraft. 

 

 Test Flight Report for flight #2 

 

 I flew my Firestar again yesterday morning for about 20-25 minutes. I was a little more confident in everything, so I took it right up to 1500 feet above the airport and flew several laps above the runway. 

 

 The aircraft needed a few pounds of forward pressure on the stick, as I have described before. However, this was at an indicated airspeed of only 45 miles per hour. A lot slower than one would expect for a properly rigged aircraft. I realized at this point that I needed to raise the leading edge of the stabilizer as a couple of people have mentioned. A "trim tab" for this would have been pretty large and bent pretty far.

 

 Also on the test flight, I paid specific attention to the rudder trim. The aircraft required five or six pounds (guess) of LEFT rudder in level flight, again at the 40-45 mile an hour speeds I was flying. It also needs left rudder on takeoff to keep it straight. This was very surprising to me because the propeller turns the "conventional" direction, meaning that it is turning the same direction as a Cessna or J-3 Cub, where you need right rudder on takeoff. The torque from the engine, especially with a high ratio gearbox and a big wide propeller, SHOULD be trying to roll and yaw the aircraft to the left, requiring right rudder. But this is the opposite of how it was in flight.

 

 I briefly let off of the rudder pressure and the airplane yawed to the right significantly. The air flow direction and the view from the seat verified this without a doubt... so it does not seem that this problem could be caused by the rudder pedals not being adjusted well.

 

 So I have a QUESTION for the experienced Kolb builders/owners here: Dies the stock Kolb engine mount have a thrust offset angle built into it??? The way this aircraft is behaving would be explained by the Kolb fuselage having several degrees of RIGHT thrust built into the engine mounts. Perhaps this would have been done to compensate for engines that turn the other direction . I'm having trouble understanding how an engine that turns a "right hand" propeller is making it steer to the RIGHT instead of left.

 

 One other thing I tried in flight was to slow the aircraft down. This seems pretty funny starting from 40 and 45 miles an hour, but I had plenty of altitude. With the vortex generators installed, and having read the flight reports from several other Kolb owners, I fully expected the aircraft to stall at 30 MPH. But as I slowed down to 35 MPH it gently stalled. I repeated this again after speeding back up to 40, to make sure I had actually stalled it the first time. Once again at 35 indicated, it provided a fairly gentle stall. No significant buffeting or shaking before the break, but a pretty gentle straight-ahead stall with the nose dropping 20 degrees when it did let go.

 

 This was disappointing, since I installed the VG's specifically to get the lower stall speed they usually provide. To be honest, I was pretty disappointed, since the old Taylorcrafts and J-3 Cubs stall just under 40 MPH, and a big part of the reason I wanted an ultralight style aircraft was to fly really slow into really short landings. 

 

 The last thing I tried to pay specific attention to was the heavy ailerons getting better at lower speeds. But again on this flight my speeds were already slow..I moved the stick left and right and it has adequate roll control, but the stick forces were far far higher than the elevator or rudder forces, and this was again at only 40 and 45 indicated. Looking out at the ailerons as I moved them, they were deflecting equally along their length... meaning that the outboard tip of the aileron waas moving as much as the inboard end of the ailerons were moving. The ailerons were not "twisting" very much. Since I am not yet familiar with the Kolb I was not able to assess whether the amount of aileron movement in flight was the same as it was on the ground (with the same amount of stick movement).

 

 I realized that I had taken too much pitch out of the propeller. The engine RPM was 5200-5300 when I was flying around at 40-45 miles an hour, and I specifically wanted to be in the "cruising" RPM range instead of maximum continuous power (which is 5800). So I will probably put two degrees more pitch into the propeller before the next test flight.

 

 After the flight I spent the rest of the day making and installing the parts to raise the leading edge of the tail. I raised the leading edge of the tail by 3/4 of an inch. using short steel extension plates.

 

 Again, my most important question for Kolbers is whether the Kolb Firestar 2 fuselage is known to have tight hand thrust offset built into the welded engine mount. Only this would explain why an engine that should be pulling the airplane left would actually be pulling it right.

 

 Bill Berle

 www.ezflaphandle.com  - safety & performance upgrade for light aircraft

 www.grantstar.net           - winning proposals for non-profit and for-profit entities

 

 --------------------------------------------

 On Thu, 8/9/18, John Hauck <jhauck(at)elmore.rr.com> wrote:

 

 Subject: RE: Firestar/HKS First Flight

 To: kolb-list(at)matronics.com

 Date: Thursday, August 9, 2018, 5:10 AM

 

 

 Hauck" <jhauck(at)elmore.rr.com>

 

 True. Some.  But not enough to get

 the job done, unless additional weight is added to equal the

 out of balance aileron.

 

 When I originally built my MKIII,

 before Kolb admitted there might be a problem with aileron

 flutter, I fabricated some really neat counter balance

 weights and attached them, very securely to 6061 plates I

 fixed to the inboard end of each aileron.  First couple

 flights went well during testing.  Then, entering the

 traffic pattern at my local airport, the MKIII went into

 violent flutter.  Snatched the stick right out of my

 hand.  Chopping power and corralling the stick as far

 back as I could get it, gets it out of flutter.  I had

 learned that exercise early on with my US and FS, but Kolb

 wasn't buying it.  Landed and promptly removed my

 beautiful counter balance weights.

 

 Right about 85 mph, where the airplane

 and I liked to cruise was right on the edge of

 flutter.  Turbulence would set it off quickly.  I

 flew the MKIII in this condition to Sun and Fun 1993, to

 Homer's to paint the Lasers, and then to Oshkosh.  At

 Oshkosh I had to fly a photo shoot with a Cessna 208. 

 He was having trouble slowing to 85 and I was going into

 flutter at 85.  It was a tough flight, but we got'er

 done.

 

 I was getting ready to do my flight

 around CONUS and up to Alaska, wondering how I was going to

 make it with the flutter problem.  I dreamed up all

 kinds of cures to keep the aileron control linkage as tight

 as possible, but I was still susceptible to flutter.  

 

 Finally, the next year at Sun and Fun

 Dick Rahill got the factory FS into severe flutter.  He

 was white as a ghost and visibly shaken when he finally got

 on the ground after flying from Lakeland South to the UL

 strip on the edge of a severe thunderstorm.  A week

 later I got a set of FS aileron counter balance weights from

 Kolb, made them fit my MKIII, and never again experienced

 aileron flutter.  It was wonderful and I was a month

 from beginning my big flight of 1994.  I had been

 flying with flutter for 10 years by this time.

 

 Don't know why my design didn't work,

 but Kolb's did.

 

 My design was ahead of the hinge line

 with bullet shaped weights like I had seen on other

 aircraft.  Guess I stuck them on the wrong end of the

 aileron because they aggravated the situation.

 

 john h

 mkIII

 Titus, Alabama

 

 

 

 

 --

victorbravo(at)sbcglobal.
Guest

Posted: Thu Aug 09, 2018 1:58 pm Post subject: Flutter / Firestar Test Flight #2

I also have to disagree regarding the Kolb being a "rudder airplane". The stock plans built Firestar has zero or maybe 1/2 degree of dihedral in the wings. At least on the plans I have. My Firestar has maybe 3 degrees total, or one and one half degree each side. I did that as much for appearance as I did for any other reason. Also, as an old washed up model airplane pilot, having a little dihedral at least gives me a CHANCE to get back on the ground safe using rudder if the entire control stick assembly falls out of the airplane 



But with this little dihedral, I cannot imagine the Kolb responding WELL to rudder like other "classic" ultralights, Quicksilvers, etc.



But... I am without a doubt the world's LOWEST time Kolb pilot, about 35 or 45 minutes total flight time in this Firestar and maybe another 30 minutes in Jimmy's Mark 3. So I can easily be wrong.



I understand completely what George is saying, I would be a much more difficult student for a UL instructor than someone with no flight time. The only thing I will disagree with George about is that as a sailplane pilot we learned to use the rudder continuously and we learned about micrometeorology, localized winds, eddy currents behind trees, etc. 



My big problem is that I remember all of this fondly but it has been 30 years. So it is not at the front of my thinking anymore. Flying a lovely old antique C-172 has spoiled me and put 9 years of rust on what were once reasonably good stick and rudder skills.



(Part of why I wanted this airplane is because I wanted to grind off all that rust. See if I could go back and find that young sharp pilot I used to know)



With all sincere respect for John H, I will leave the spins and aerobatics in a Kolb to him. He recently posted on the Kolb List "If you want to do aerobatics go get a Pitts..." Excellent advice 



Bill Berle

www.ezflaphandle.com  - safety & performance upgrade for light aircraft

www.grantstar.net           - winning proposals for non-profit and for-profit entities



--------------------------------------------

On Thu, 8/9/18, John Hauck <jhauck(at)elmore.rr.com> wrote:



 Subject: RE: Flutter / Firestar Test Flight #2

 To: kolb-list(at)matronics.com

 Date: Thursday, August 9, 2018, 2:35 PM

 

 

 Hauck" <jhauck(at)elmore.rr.com>

 

 I can't speak for other ULs, only Kolbs

 and a couple flights in the Howland Honey Bee (too many

 years ago to remember all its flight characteristics). 

 IMHO Kolbs are not rudder airplanes, based on my own flying

 experience with them.  I've found that the Kolbs are

 more aileron aircraft, with a little rudder to keep them

 trimmed, and of course more rudder on takeoff, landing, and

 taxiing.  Maybe I'm different because I still have a

 lot of rotary wing stuck in my head after all these

 years.  I don't know.

 

 Once the Kolb is trimmed up in yaw, I

 can put my feet on the deck, and fly the Kolb with aileron

 and elevator, trim ball centered, making coordinated

 turns.  The aileron geometry is really good on

 Kolbs.  Homer got that right.

 

 That's my experience and I am sticking

 to it.  I can't speak for other ULs because I have only

 flown one other UL other than Kolbs, Burt Howland's little

 biplane, the Honey Bee.  It was a little doll

 baby.  Burt and Ellen Howland, rest in peace my

 friends, attended The Ultralight Flight Farm in NY, 1988-89,

 where I met them.  They were a lot of fun.  I

 didn't ask, but Burt offered me the chance to fly his

 classic looking little bird.  Landing was a no

 brainer.  Set it up on final at 25 mph, hold that

 attitude, and a tiny flare, it's on the ground.  I

 can't remember if the Honey Bee was a rudder plane or

 not.  Been too long ago.  Certainly wasn't an

 Aeronca Champ.  

 

 john h

 mkIII

 Titus, Alabama

 

 

 

 

 

 

 --

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu Aug 09, 2018 2:22 pm Post subject: Flutter / Firestar Test Flight #2

My last aerobatic maneuver was 15 March 1990...  Took 6 years from the time I first started flying Kolbs to learn my lesson.  I still like to fly somewhat aggressively, but without aerobatics.



john h

mkIII

Titus, Alabama





--

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

gdhelton(at)gmail.com
Guest

Posted: Thu Aug 09, 2018 2:39 pm Post subject: Flutter / Firestar Test Flight #2

I wasn’t implying that Kolb’s are rudder controlled aircraft. I apologize if that was way it was interrupted. The Kolb is the exception. My instructing was done in Spectrum Beavers and Quiksilvers. High dihedral makes very stable, very rudder oriented aircraft.

My Firestar is also aileron oriented. I to can cruise around with my feet flat on the floor. And I love it. Homer did get it right. That being said, my Firestar on takeoff and landing requires good foot work to be flown properly. Especially in crosswind conditions. Lazy feet and improper use of flight controls use on the ground make for expensive repairs.  Time and money I’d rather spend on flying.

My point is that you have learn to fly and enjoy your airplane, before you go making it a different airplane. 

George H. 

Firestar, FS100, 2702 Hirth 

14GDH 

Mesick, Michigan 

gdhelton(at)gmail.com



Sent from my iPhone



[quote] On Aug 9, 2018, at 5:57 PM, Bill Berle <victorbravo(at)sbcglobal.net> wrote:

 

 

 

 I also have to disagree regarding the Kolb being a "rudder airplane". The stock plans built Firestar has zero or maybe 1/2 degree of dihedral in the wings. At least on the plans I have. My Firestar has maybe 3 degrees total, or one and one half degree each side. I did that as much for appearance as I did for any other reason. Also, as an old washed up model airplane pilot, having a little dihedral at least gives me a CHANCE to get back on the ground safe using rudder if the entire control stick assembly falls out of the airplane 

 

 But with this little dihedral, I cannot imagine the Kolb responding WELL to rudder like other "classic" ultralights, Quicksilvers, etc.

 

 But... I am without a doubt the world's LOWEST time Kolb pilot, about 35 or 45 minutes total flight time in this Firestar and maybe another 30 minutes in Jimmy's Mark 3. So I can easily be wrong.

 

 I understand completely what George is saying, I would be a much more difficult student for a UL instructor than someone with no flight time. The only thing I will disagree with George about is that as a sailplane pilot we learned to use the rudder continuously and we learned about micrometeorology, localized winds, eddy currents behind trees, etc. 

 

 My big problem is that I remember all of this fondly but it has been 30 years. So it is not at the front of my thinking anymore. Flying a lovely old antique C-172 has spoiled me and put 9 years of rust on what were once reasonably good stick and rudder skills.

 

 (Part of why I wanted this airplane is because I wanted to grind off all that rust. See if I could go back and find that young sharp pilot I used to know)

 

 With all sincere respect for John H, I will leave the spins and aerobatics in a Kolb to him. He recently posted on the Kolb List "If you want to do aerobatics go get a Pitts..." Excellent advice 

 

 Bill Berle

 www.ezflaphandle.com  - safety & performance upgrade for light aircraft

 www.grantstar.net           - winning proposals for non-profit and for-profit entities

 

 --------------------------------------------

 On Thu, 8/9/18, John Hauck <jhauck(at)elmore.rr.com> wrote:

 

 Subject: RE: Flutter / Firestar Test Flight #2

 To: kolb-list(at)matronics.com

 Date: Thursday, August 9, 2018, 2:35 PM

 

 

 Hauck" <jhauck(at)elmore.rr.com>

 

 I can't speak for other ULs, only Kolbs

 and a couple flights in the Howland Honey Bee (too many

 years ago to remember all its flight characteristics). 

 IMHO Kolbs are not rudder airplanes, based on my own flying

 experience with them.  I've found that the Kolbs are

 more aileron aircraft, with a little rudder to keep them

 trimmed, and of course more rudder on takeoff, landing, and

 taxiing.  Maybe I'm different because I still have a

 lot of rotary wing stuck in my head after all these

 years.  I don't know.

 

 Once the Kolb is trimmed up in yaw, I

 can put my feet on the deck, and fly the Kolb with aileron

 and elevator, trim ball centered, making coordinated

 turns.  The aileron geometry is really good on

 Kolbs.  Homer got that right.

 

 That's my experience and I am sticking

 to it.  I can't speak for other ULs because I have only

 flown one other UL other than Kolbs, Burt Howland's little

 biplane, the Honey Bee.  It was a little doll

 baby.  Burt and Ellen Howland, rest in peace my

 friends, attended The Ultralight Flight Farm in NY, 1988-89,

 where I met them.  They were a lot of fun.  I

 didn't ask, but Burt offered me the chance to fly his

 classic looking little bird.  Landing was a no

 brainer.  Set it up on final at 25 mph, hold that

 attitude, and a tiny flare, it's on the ground.  I

 can't remember if the Honey Bee was a rudder plane or

 not.  Been too long ago.  Certainly wasn't an

 Aeronca Champ.  

 

 john h

 mkIII

 Titus, Alabama

 

 

 

 

 

 

 --

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu Aug 09, 2018 3:00 pm Post subject: Flutter / Firestar Test Flight #2

Absolutely!  I agree with you 100%.  Glad you set me straight.



Every once in a while we get a rash of new pilots spreading the main gear and breaking airplanes because of what our buddy Pat Ladd, RIP, in England, called "Kolb quit".  For some reason folks could not understand why the Kolb had this nasty characteristic of falling out of the sky two or more feet above the air strip.  Poor old Kolb had nothing to do with "Kolb quit", but it had everything to do with pilot error, not flying the aircraft.  Can't blame poor pilotage on the airplane.  If we keep the Kolb above stall speed, it won't stall and it will not commit "Kolb quit".



Best way to learn to fly the Kolb is get out there and fly a lot, every day if you can.  The more you fly the more you learn about your Kolb.  It is a super safe aircraft if flown reasonably.  Normally, only time I broke something was when I was pushing the limits, exploring unknown territory.  You couldn't pay me to do that stuff again.  I don't have the guts or I have a lot more sense now than I did 25-30 years ago.



I believe in learning to fly the Kolb engine off, make dead stick landings.  When the engine surprises you by getting real quiet, you'll know just what to do and how the aircraft will be with a dead stick.  It is different from an idling prop.



The main thing is get out there and have fun with your Kolb.

john h

mkIII

Titus, Alabama





--

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

gdhelton(at)gmail.com
Guest

Posted: Thu Aug 09, 2018 3:27 pm Post subject: Flutter / Firestar Test Flight #2

Amen to that John. After living in SoCal for 43 years it’s taken some getting use to only having 4 or 5 flyable months a year living in the great white north. I’m over 70 now and still enjoy every moment that I get to spend in my old Firestar. I never did like that “ Kolb Quit” crap. There is no substitute for real deadsticks. I never soloed a student without them experiencing one for real.

George H.

Firestar, FS100, 2702 Hirth 

14GDH

Mesick, Michigan 

gdhelton(at)gmail.com

Sent from my iPhone



[quote] On Aug 9, 2018, at 7:00 PM, John Hauck <jhauck(at)elmore.rr.com> wrote:

 

 

 

 Absolutely!  I agree with you 100%.  Glad you set me straight.

 

 Every once in a while we get a rash of new pilots spreading the main gear and breaking airplanes because of what our buddy Pat Ladd, RIP, in England, called "Kolb quit".  For some reason folks could not understand why the Kolb had this nasty characteristic of falling out of the sky two or more feet above the air strip.  Poor old Kolb had nothing to do with "Kolb quit", but it had everything to do with pilot error, not flying the aircraft.  Can't blame poor pilotage on the airplane.  If we keep the Kolb above stall speed, it won't stall and it will not commit "Kolb quit".

 

 Best way to learn to fly the Kolb is get out there and fly a lot, every day if you can.  The more you fly the more you learn about your Kolb.  It is a super safe aircraft if flown reasonably.  Normally, only time I broke something was when I was pushing the limits, exploring unknown territory.  You couldn't pay me to do that stuff again.  I don't have the guts or I have a lot more sense now than I did 25-30 years ago.

 

 I believe in learning to fly the Kolb engine off, make dead stick landings.  When the engine surprises you by getting real quiet, you'll know just what to do and how the aircraft will be with a dead stick.  It is different from an idling prop.

 

 The main thing is get out there and have fun with your Kolb.

 

 

 john h

 mkIII

 Titus, Alabama

 

 

 

 

 --

johngilpin

Joined: 23 Mar 2011
Posts: 93
Location: 004

Posted: Fri Aug 10, 2018 12:34 am Post subject: Flutter / Firestar Test Flight #2

Sure wish folks would get into the habit of deleting the ever increasing tail of previous posts that follow their post.......



JG

russk50(at)gmail.com
Guest

Posted: Fri Aug 10, 2018 4:50 pm Post subject: Flutter / Firestar Test Flight #2

Right on, JG - hope some people listen

Russ K



 	  Quote: 	
		   On Aug 10, 2018, at 4:33 AM, JC Gilpin <j.gilpin(at)bigpond.com> wrote:

 

 Sure wish folks would get into the habit of deleting the ever increasing tail of previous posts that follow their post.......

 

 JG

Mcabbage

Joined: 08 Sep 2013
Posts: 41
Location: MA.

Posted: Mon Aug 13, 2018 8:03 am Post subject: Re: Flutter / Firestar Test Flight #2

Excellent discussion, im not trying to hijack your post Bill

but may i ask as a zero time Kolb pilot what is the proper way to fly 

and land an engine out Kolb?

Thanks Mike

_________________
2007 Firestar 2 503 N203SD
Moster 185 Flattop PPG/Sky K2 Paraglider
Trike Buggy Soaring Trike & Northwing Stratus XP

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Mon Aug 13, 2018 8:28 am Post subject: Flutter / Firestar Test Flight #2

Not much different than powered landing.  Only thing is you don't get a

second chance to do it.  The Kolb will glide better dead stick and with the

engine at idle.  



We should all be constantly looking for forced landing areas as we fly.

Most likely the engine will quit when you least expect it, not necessarily

when you have a nice big hay field to land in.



If you can shoot your approach at idle all the way to the ground, you can do

a dead stick.  



I've been flying 50 years next month.  I still practice engine failures with

dead stick landings.  When the time comes I want to be able to execute the

forced landing with ease.



john h

mkIII

Titus, Alabama





 

Excellent discussion, im not trying to hijack your post Bill

but may i ask as a zero time Kolb pilot what is the proper way to fly 

and land an engine out Kolb?

Thanks Mike



--------

2007  Firestar 2 503  N203SD

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Display posts from previous:

	Matronics Email Lists Forum Index -> Kolb-List	All times are GMT - 8 Hours Goto page 1, 2 Next
Page 1 of 2

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum