Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

Duellist maiden- with Jett FIRE 50's and pipes

Reply

Old 05-22-2007, 06:06 AM
  #1  
Build-n-flyer-RCU
Senior Member
Thread Starter
My Feedback: (4)
 
Build-n-flyer-RCU's Avatar
 
Join Date: Sep 2002
Location: Evans, GA
Posts: 1,053
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Duellist maiden- with Jett FIRE 50's and pipes

I usually post in the twins forum but Bob and I thought you extreme speed guys might like to take a look at this one.

This is a vintage Duellist that the wife bought for me at Perry a couple of years ago. I added new gear, a pair of rear exhaust Jett 50's and tuned pipes. And did a whole bunch of creative work to get all the new stuff in the old plane and re-finish it without messing up the cool graphics. I finally got it in the air this past weekend.

The link will take you to my warbird page. Scroll down to see video of the Duellist. The video is a real hoot, there's not much showing the plane actually flying, it disappears from camera view a fraction of a second after the takeoffs. But some of the comments are priceless.

[link=http://flytrca.org/video1.html]Video Page[/link]

The Jetts are spinning 9.5x7 props just shy of 18,000 RPM peak, richened to around 17,400 to fly. The plane is fast, real fast! I got a little flutter on the last high speed pass down the runway so I have a little work to do. But all in all... success!!

Walt
Attached Thumbnails Click image for larger version

Name:	Yw67823.jpg
Views:	8
Size:	74.6 KB
ID:	689279   Click image for larger version

Name:	Bw71234.jpg
Views:	10
Size:	63.8 KB
ID:	689280  
Build-n-flyer-RCU is offline  
Reply With Quote
Old 05-22-2007, 09:32 AM
  #2  
Mike Connor
Senior Member
My Feedback: (5)
 
Mike Connor's Avatar
 
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

My friend had a Duellist and it was pretty fast, even without the Jetts. That video work reminds me of my X GF with her hands on the camera. Nice job.
Attached Thumbnails Click image for larger version

Name:	Om31971.jpg
Views:	8
Size:	56.5 KB
ID:	689343  
Mike Connor is offline  
Reply With Quote
Old 05-22-2007, 01:30 PM
  #3  
Build-n-flyer-RCU
Senior Member
Thread Starter
My Feedback: (4)
 
Build-n-flyer-RCU's Avatar
 
Join Date: Sep 2002
Location: Evans, GA
Posts: 1,053
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

The wife is actually pretty good with the camera and has taken some very nice video of my planes. But this one was a challenge. She was just a little frustrated by it.

You guys may be able to help me sort out my high-speed flutter issue.

We gradually opened it up down the runway without any problems until I finally gave it full throttle and let it rip. As it went by we could hear flutter, so I backed off and landed it. I couldn't "feel" it in the air and inspecting the plane shows no real problems. One of the ailerons may be looser than it was but only slightly. On any other plane I wouldn't consider it loose at all.

The plane was built for speed, glassed and painted with plastic pin hinges spaced about every 2" on all the control surfaces. The gaps are not sealed but they are extremely tight. The elevator halves each have a control horn and pushrod, and the halves are wire-joined. All the pushrods have soldered Sulivan clevises on both ends. The only weakness in the design is that torque rods are used to activate the ailerons from a pair of servos mounted at the center of the wing. I can relocate the aileron servos into the wings and eliminate the torque rods, but would rather not since the current setup is very clean.

All of the servos are JR, either digitals or high-torque analogs. The plane trimmed out with all of the surfaces visually neutral so it doesn't seem to have any incidence problems.

What do you think? Will sealing the gaps in the control surfaces alone eliminate the problem? What about replacing the aileron pushrods with wood to eliminate any flex there? Or should I just bite the bullet and put the servos in the wings..

By the way this is the first plane that I have ever had flutter with, but then I never built one for this kind of speed, either...

Walt
Build-n-flyer-RCU is offline  
Reply With Quote
Old 05-22-2007, 03:54 PM
  #4  
Mike Connor
Senior Member
My Feedback: (5)
 
Mike Connor's Avatar
 
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

I built a Shrike 40 that had flutter. Every thing was tight but I over sanded the leading edge of the aileron. The rule is that the leading edge of the aileron must be at least as thick as the trailing edge of the wing it mates to. I refused to put in wing servos because of weight and drag. Sealing the gap helped but I finally used a narrow strip 1/64 ply and attached it to the trailing edge of the wing and let it go over the gap. No more flutter. Even in a dive with a Jett 50 on it. I have seen gap tape that is similar to what I did and it is popular with the glider guys.
Attached Thumbnails Click image for larger version

Name:	Fd91962.jpg
Views:	9
Size:	17.0 KB
ID:	689554  
Mike Connor is offline  
Reply With Quote
Old 05-22-2007, 09:01 PM
  #5  
Build-n-flyer-RCU
Senior Member
Thread Starter
My Feedback: (4)
 
Build-n-flyer-RCU's Avatar
 
Join Date: Sep 2002
Location: Evans, GA
Posts: 1,053
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

Thanks Mike for the advice. You are convincing me think that the first thing to do is to take care of the gaps to get rid of the source of the problem. If there is no tendency to flutter then the existing linkage should be fine.

Your solution looks great but unfortunately it would be hard to adapt to my airplane. I would need grind off the paint and glass in order to add new wood. And then refinishing with the automotive color/clearcoat would be quite a job.

I usually seal gaps by just ironing in some covering. But that doesn't smooth over the hinge space like what you did.

Walt
Build-n-flyer-RCU is offline  
Reply With Quote
Old 05-22-2007, 10:23 PM
  #6  
HighPlains
My Feedback: (1)
 
Join Date: Mar 2003
Location: Over da rainbow, KS
Posts: 5,085
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

Tape the end of the ailerons solid to the wing tips. Long strip ailerons tend to be too flexible for high speed, especially with the addition of a torque rod.
HighPlains is offline  
Reply With Quote
Old 05-23-2007, 12:45 AM
  #7  
Mike Connor
Senior Member
My Feedback: (5)
 
Mike Connor's Avatar
 
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

ORIGINAL: Build-n-flyer-RCU


I usually seal gaps by just ironing in some covering. But that doesn't smooth over the hinge space like what you did.

Walt
You can try your method but if it doesn't work you can get this from Hobby Lobby. Don't remember it costing that much from a sailplane place that used to carry it. You might try a search. I also think it is clear so looks wont be a problem.

GR63 Control Surface Gap Tape,
16 feet ..... $ 35.90
IN STOCK
13/16" wide, 0.2mm thick, half of it sticks to airfoil surface. The thicker, non-stick portion stays pressed against the control surface and covers the control surface gap.
Mike Connor is offline  
Reply With Quote
Old 05-23-2007, 05:58 AM
  #8  
Build-n-flyer-RCU
Senior Member
Thread Starter
My Feedback: (4)
 
Build-n-flyer-RCU's Avatar
 
Join Date: Sep 2002
Location: Evans, GA
Posts: 1,053
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

Mike thanks for the hinge tape info. I will order some and see if it looks like it would work.

Yes, the strip ailerons are not ideal for a high-speed airplane. But they are built up and glassed so they are much stiffer than those on a trainer. Restricting the outer ends is not an option.

This has been a "challenge" airplane for me from the get-go, but I am very close to making it a reliable flyer. I only got the flutter when I really let it go, so hopefully minor improvements should do the trick.

Walt
Build-n-flyer-RCU is offline  
Reply With Quote
Old 05-23-2007, 06:53 AM
  #9  
Ed Smith
Senior Member
 
Join Date: Dec 2001
Location: Brantford, ON, CANADA
Posts: 3,305
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

Hinges have no effect on aileron flutter. Think about it, the control surface must move freely on the hinges.

Do as High Plains suggested. Apply tape across the outboard end of the aileron. Do not tape the whole end. Apply the tape diagonally across the end. Start with half of the aileron width taped and go from there.

Ed S
Ed Smith is offline  
Reply With Quote
Old 05-23-2007, 09:18 AM
  #10  
Build-n-flyer-RCU
Senior Member
Thread Starter
My Feedback: (4)
 
Build-n-flyer-RCU's Avatar
 
Join Date: Sep 2002
Location: Evans, GA
Posts: 1,053
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

I am not exactly sure what you and High Plains are suggesting but very interested.

Correct me if I am wrong. If the ends are fixed solidly to the wingtips then the ailerons would have to twist in order to deflect. I think that the ailerons are too stiff for this. And I would be concerned about the impact on general flight characteristics. The plane is designed to be a sport flyer so it needs a good amount of deflection across the length of the ailerons to fly right. I believe low rate is currently set at 1/2 inch up and down and it is not at all sensitive flying with this rate.

Ed I am not sure exactly what you are suggesting, can you provide more detail? Is the idea to add resistance to deflection at the end of the ailerons without locking them up? Do you have a sketch or photo to help make sure I understand?

Walt
Build-n-flyer-RCU is offline  
Reply With Quote
Old 05-23-2007, 09:56 AM
  #11  
bob27s
My Feedback: (19)
 
bob27s's Avatar
 
Join Date: Apr 2002
Location: Cleveland, OH
Posts: 5,576
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

Seal the hinge gaps. Clear monokote, tape, what ever ya have.

Tight gaps and good hinges do not count.

Flutter is by and large about pressure differential, and rapid changes in pressure. Eliminate the cross-flow path.
bob27s is offline  
Reply With Quote
Old 05-23-2007, 12:16 PM
  #12  
MJD
My Feedback: (1)
 
MJD's Avatar
 
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,629
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

ORIGINAL: Build-n-flyer-RCU

The plane was built for speed, glassed and painted with plastic pin hinges spaced about every 2" on all the control surfaces. The gaps are not sealed but they are extremely tight. The elevator halves each have a control horn and pushrod, and the halves are wire-joined. All the pushrods have soldered Sulivan clevises on both ends. The only weakness in the design is that torque rods are used to activate the ailerons from a pair of servos mounted at the center of the wing. I can relocate the aileron servos into the wings and eliminate the torque rods, but would rather not since the current setup is very clean.
Seems to me a pretty clean installation could be made by tucking the servos into the rear of the motor nacelles?

Nice aircraft, and you did what a number of others were probably thinking they would like to do!

Hope sealing the hinge lines fixes your flutter problem. Then let 'er rip!

MJD
MJD is offline  
Reply With Quote
Old 05-23-2007, 04:55 PM
  #13  
Ed Smith
Senior Member
 
Join Date: Dec 2001
Location: Brantford, ON, CANADA
Posts: 3,305
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

Ed I am not sure exactly what you are suggesting, can you provide more detail? Is the idea to add resistance to deflection at the end of the ailerons without locking them up? Do you have a sketch or photo to help make sure I understand?
That is correct. The picture shows the taped corner of the outboard end of the aileron. That is a Nelson powered Pylon Racer wing. Just catching the corner of the aileron stopped a rather nasty flutter and made no difference to the control response. Sorry about the flash reflection but I think you get the idea.

Ed S
Attached Thumbnails Click image for larger version

Name:	Tr51545.jpg
Views:	7
Size:	50.4 KB
ID:	690173  
Ed Smith is offline  
Reply With Quote
Old 05-23-2007, 05:35 PM
  #14  
Build-n-flyer-RCU
Senior Member
Thread Starter
My Feedback: (4)
 
Build-n-flyer-RCU's Avatar
 
Join Date: Sep 2002
Location: Evans, GA
Posts: 1,053
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

Thanks everyone for the suggestions! I will probably leave the linkage as is and work on sealing the gaps. The gap tape looks interesting so I will order some just to see what I think. And the tape at the end of the ailerons also looks like a good idea.

With the flutter gone then the only thing left will be to work on getting the engines to run together better at low-mid throttle. Luckily this doesn't make much difference in flight, but it does make take-offs a bit interesting.

Other than that the plane flies great! Very stable but nimble both at low and high speeds, no problems with the retracts, easy to land, etc so I am very happy. I started this project with the idea of making the plane a real attention-getter. I think that a lot of folks thought I was a bit nuts but I can see it all coming together.

Walt
Build-n-flyer-RCU is offline  
Reply With Quote
Old 05-23-2007, 07:59 PM
  #15  
Ed_Moorman
My Feedback: (1)
 
Ed_Moorman's Avatar
 
Join Date: Jan 2002
Location: Shalimar, FL
Posts: 4,059
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

Walt,

I use 3M clear packaging tape on all my planes.

Get someone to hold your plane, crank it up, then go to the dual throttle curves. I would leave the right engine-the primary-alone and set the curve for the mate engine. You can blip it up or down to match, even tach both. You can set them at 7 points. I love all the twin engine settings on the 9303.
Ed_Moorman is offline  
Reply With Quote
Old 05-23-2007, 08:48 PM
  #16  
HighPlains
My Feedback: (1)
 
Join Date: Mar 2003
Location: Over da rainbow, KS
Posts: 5,085
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

3M makes a plastic tape under the Scotch brand that is labeled as "Decorate and Repair Tape" found in better hardware store. It is very flexible and nearly indestructible, something that packing tape lacks. However for sealing hinge lines, nothing is better than a 3M medical tape call "Blenderm". It is both flexible and extremely thin, found at medical supply stores.

You can get away with a multitude of design errors, construction errors, and poor control geometry..........at slow speeds.

But when you start pushing the speed on any model, flutter becomes an issue. When you stiffen the aileron with glass, you raised the natural frequency of the surface and no doubt that bought you a much higher speed before the onset of flutter. But one of the methods that full scale aircraft designers use (mass balance) is difficult to implement on models.

However taping the end of the aileron has worked quite well for me on dozens of models in thousands of flights at speeds much much faster. I would tape it solid, and fly it to prove no flutter at full speed. If that solves it, expand the performance envelope with a slight dive. You can also sometime excite flutter by giving a quick pulse on the stick and releasing. The point is to test for it early on while you are looking for it, instead of accidentally finding a failure mode later.

If the full tape does resolve it, then you can slice into the tape a bit at a time to increase throw and retest to find the limits.

Thanks for sharing a great project.
HighPlains is offline  
Reply With Quote
Old 05-24-2007, 06:03 AM
  #17  
Build-n-flyer-RCU
Senior Member
Thread Starter
My Feedback: (4)
 
Build-n-flyer-RCU's Avatar
 
Join Date: Sep 2002
Location: Evans, GA
Posts: 1,053
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

Ed, I see you found me over here. Yes the 9303 throttle curve features are outstanding for twins, and you know that the synch on the YS's in my 'Widow and OS's in my Twin-Air are near about perfect.

But the Jetts are different animals and coming up on the pipes is like hitting the afterburners. And since the engines are still breaking in every run is a bit different. Hopefully I should have them dialed in much better by the time we meet up at MOM next month.

HighPlains, I know I am in new territory and that's why I appreciate all the advice. Speed planes are few and far between around here so local help is very limited. I never heard of taping the ends of the ailerons like you guys are suggesting but I definitely plan to play around with it and give it a shot. And a trip to a medical supplies store is now on my list.

As for putting the plane in a dive under power, I am a long way from doing that! I am a big believer in easing into the performance envelope slowly to identify and resolve problems. I have too much time and money in this airplane to invite disaster!

Walt
Build-n-flyer-RCU is offline  
Reply With Quote
Old 05-24-2007, 05:26 PM
  #18  
Strykaas
Senior Member
 
Join Date: Mar 2003
Location: New York, NY
Posts: 4,571
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

nothing is better than a 3M medical tape call "Blenderm"
I totally agree with that.
Strykaas is offline  
Reply With Quote
Old 05-24-2007, 06:09 PM
  #19  
proptop
My Feedback: (8)
 
proptop's Avatar
 
Join Date: Oct 2002
Location: Rome, NY
Posts: 7,022
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

It also works real good as hinge tape for your little profile electric "foamy"

I took mine out late last night and flew in the Home Depot (well lit ) parking lot...

Got it up to a "blistering" 17 m.p.h.![X(] or at least that's what it looked like...
(this IS the "Extreme Speed" forum after all...right!?)
proptop is offline  
Reply With Quote
Old 05-25-2007, 09:31 AM
  #20  
bob27s
My Feedback: (19)
 
bob27s's Avatar
 
Join Date: Apr 2002
Location: Cleveland, OH
Posts: 5,576
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

I agree... the blenderm is great stuff

not expensive either, and sticks very well.
bob27s is offline  
Reply With Quote
Old 05-25-2007, 11:10 AM
  #21  
daven
Senior Member
My Feedback: (1)
 
Join Date: Dec 2001
Location: Waseca, MN
Posts: 8,455
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

Blenderm, and the decorating tape, work well. I usually can find the 3m Decorating tape at Ace Hardware stores.

If you can't, www.darrolcady.com stocks both the Blenderm and decorating tapes.

Neat stuff, I buy it by the 6 pack.
daven is offline  
Reply With Quote
Old 06-11-2007, 07:59 PM
  #22  
Build-n-flyer-RCU
Senior Member
Thread Starter
My Feedback: (4)
 
Build-n-flyer-RCU's Avatar
 
Join Date: Sep 2002
Location: Evans, GA
Posts: 1,053
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

The good news, I got the engines synched much better and resolved the flutter problem on my Duellist.

The bad news, I re-kitted the plane Sunday due to a dumb landing error on my part (see the twins forum for details). It was my first crash in 3 years of flying twins.

It will take a while to get it repaired and flying again.

A new question- with the flutter gone I was able to get the engines completely up on the pipes and really build serious speed. But it would eventually reach a speed where the airplane began oscillating up and down (porpoising?). No flutter noise, just a slight pitch up then down maybe a few times per second. Has anyone seen this before? What could cause it?

Walt
Build-n-flyer-RCU is offline  
Reply With Quote
Old 06-12-2007, 02:13 PM
  #23  
bob27s
My Feedback: (19)
 
bob27s's Avatar
 
Join Date: Apr 2002
Location: Cleveland, OH
Posts: 5,576
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

ouch.......

not sure on the porpousing ...... usually something like that come from a 'too sharp' leading edge on the wing - where the plane wants to hunt up and down a bit. But I do not recall seeing that being the case in your photos.

Other than that... the obvious stuff.... like a servo that did not want to properly center, or a linkage that "buzzed" and flexed a tiny bit at a certain power setting.

Bob
bob27s is offline  
Reply With Quote
Old 06-12-2007, 08:34 PM
  #24  
Build-n-flyer-RCU
Senior Member
Thread Starter
My Feedback: (4)
 
Build-n-flyer-RCU's Avatar
 
Join Date: Sep 2002
Location: Evans, GA
Posts: 1,053
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

The oscillation only began at speeds well beyond what the Duellist was designed for (throttles wide open during level flight) and it was very repeatable. If I need to make any changes to eliminate it this is the right time since I have a good bit of rebuild work to do anyway.

The oscillation was all pitch so if it was a servo it would have to be to the elevator. The linkage is split with a separate horn on each elevator half in addition to a joiner wire, and good and tight- no play at all. I had a high torque servo on it, during the rebuild I will try a good digital.

The leading edge on the wing looks right to me, not terribly sharp, but there is another factor that I thought may come into play. The wing is built with wash-in at the wingtips. It seems very purposely done- dead even on both sides according to my meter. I was actually a bit worried about it until I flew the plane and found it to be rock stable, with no tip-stall tendency at all. In fact it was probably the best handling sport plane I have flown, single or twin. But maybe at very high speeds the wash-in could cause some problems?

Walt
Build-n-flyer-RCU is offline  
Reply With Quote
Old 06-12-2007, 10:59 PM
  #25  
rcflyer1970
My Feedback: (212)
 
rcflyer1970's Avatar
 
Join Date: Dec 2004
Location: SUN CITY, AZ
Posts: 191
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Duellist maiden- with Jett FIRE 50's and pipes

Bummer[], sorry to hear of the landing mishap, I had a similar ocillation and it did turn out to be the sharpness of the leading edge, I over pointed it and it would hunt, good luck on the repairs.
rcflyer1970 is online now  
Reply With Quote

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service