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

Shrike 40 with thinner airfoil

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Old 12-20-2012, 11:56 PM
  #126
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Default RE: Shrike 40 with thinner airfoil


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ORIGINAL: speedracerntrixie

I'm wondering if your Picco is intended for pattern use the same as my Rossi was. My Rossi did not work at all with the short pipe/high RPM approach even though I raised the exhaust port .030. What ended up working the best was a total pipe length of 25'' and a large prop. In this case an 11X11. I did try a pipe length of 18'' with an APC 9X10 and the airplane was a dog. Changed to a longer header for a total length 21'' and got best results with a 10X10. Finally had a section welded to the pipe that increased the inlet ID to 7/8'' and made up a 7/8''x 12'' header for a total length of 25'' and installed a Picco 12mm carb. First tried an 11X10 and it was a huge difference in speed. Tried an 11X11 and was even faster, 11X12 and the speed dropped. Now the 60 is going into a classic pattern airplane and a Rossi 90 is on the way. I'm going to start off with the 25'' pipe and 11X12 and see what she does. Lots of engine for a 6 lb 450 sq in airplane lol

I just pulled the Rossi 61 and pipe out of my race plane to get it ready for the arrival of the 90. You can see that the header/pipe is quite long in comparison. You have to love that carb. I'm assuming that the Picco the OP has is fitted with an 8mm carb indicating that it was intended for pattern. It may just be that it develops it's peak power at a lower RPM like the Rossi does.

It probably is , the stock exhaust timing is 150°.

Do you have a tach reading with the 9x10 APC ??? would be great if you have it to compare it with the Picco.

On what plane do you have mounted this egine ???

The inner measure (on top) of the carb of mi Picco is 16mm , the below measure is 9mm.
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Old 12-21-2012, 12:02 AM
  #127
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Default RE: Shrike 40 with thinner airfoil


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ORIGINAL: Quikturn

Speedboy, what an awesome job you did on your Shrike. I love it!

Good luck on your flight.

I built one a few years ago. It had a piped OS 40 FSR abc engine. It was fast enough for me. My only mod was to add a dual rudder set up. That was great for snap rolls and spins.

Unfortunately, I sold it but I made rib & former templates so I may have to build another one. My thought was to make it with a twin boom tail to resemble a BVM Bobcat. I have a YS 45FR looking for something to do.
Thanks Quikturn , you did also a very good job there.

I like your Shrike too since the first time I saw it , very clean job.
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Old 12-21-2012, 09:17 AM
  #128
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Default RE: Shrike 40 with thinner airfoil

Speedboy
Lets see...I reduced the height of the airfoils. Tried increasing the rake of the wing and reduced the wing width. Moved the twin vertical stabilizers inboard like the F15. Reduced the height of the vertical stabilizers. That's about it. There really is not a lot you can do to the original airframe. None of the mods had any effect with regards to speed. Only stability. In other words If it aint broke, dont fix it. The basic formula for speed is weight-RPM-HP. My latest creation on the table right now is the basic Shrike 10 which will be powered by a modified Buggy engine. I was able to modify the crankshaft to accomodate a prop. The carb was switched out to a Perry of the same intake diameter. The head was cut down in height and turned down in diameter. The engine is a Thunder Tiger 28 F.I.R.E. with a Mac tuned pipe. I did not want to spend a ton of money on the more advanced buggy engines available. This is just an experiment after all. The engine achieved 19.5K on my test stand. I don't recall the exact prop I used. Probably a 7 or 8 inch. This is considerably more RPM than a comparable air engine of the same size. So it will be interesting to see how it all plays out.
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Old 12-21-2012, 01:58 PM
  #129
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Default RE: Shrike 40 with thinner airfoil


Quote:
ORIGINAL: SpeedBoy


Quote:
ORIGINAL: speedracerntrixie

I'm wondering if your Picco is intended for pattern use the same as my Rossi was. My Rossi did not work at all with the short pipe/high RPM approach even though I raised the exhaust port .030. What ended up working the best was a total pipe length of 25'' and a large prop. In this case an 11X11. I did try a pipe length of 18'' with an APC 9X10 and the airplane was a dog. Changed to a longer header for a total length 21'' and got best results with a 10X10. Finally had a section welded to the pipe that increased the inlet ID to 7/8'' and made up a 7/8''x 12'' header for a total length of 25'' and installed a Picco 12mm carb. First tried an 11X10 and it was a huge difference in speed. Tried an 11X11 and was even faster, 11X12 and the speed dropped. Now the 60 is going into a classic pattern airplane and a Rossi 90 is on the way. I'm going to start off with the 25'' pipe and 11X12 and see what she does. Lots of engine for a 6 lb 450 sq in airplane lol

I just pulled the Rossi 61 and pipe out of my race plane to get it ready for the arrival of the 90. You can see that the header/pipe is quite long in comparison. You have to love that carb. I'm assuming that the Picco the OP has is fitted with an 8mm carb indicating that it was intended for pattern. It may just be that it develops it's peak power at a lower RPM like the Rossi does.

It probably is , the stock exhaust timing is 150°.

Do you have a tach reading with the 9x10 APC ??? would be great if you have it to compare it with the Picco.

On what plane do you have mounted this egine ???

The inner measure (on top) of the carb of mi Picco is 16mm , the below measure is 9mm.

I don't have RPM figures for the 9X10. I would estimate 15K. All I know is that the airplane was too slow. The Rossi has a ton of torque and after I decided to talk with a few guys that were flying pattern with these engines did I understand that I should have been taking advantage of that torque. The carb barrel that slips into the egine crankcase is 16mm. That is shared on most OPS, Rossi and Picco engines of this size. The 9mm is not too bad but you can find bigger carbs for it. The Picco 12mm worked really well for me once I figured out how to get good fuel delivery to it. The bigger the carb, the less suction it has to pull fuel from the tank. In my case the engine was going lean it the turns. I could have gotten more power from this setup if I had opened up the intake timing a bit. I choose not to do that as we have a rule that our race engines have to be able to idle at 4,000 rpm or less, Doing so would also have moved the powerband up some. Notice in the picture, the pipe barely exits the fuse. On the current setup the pipe comes out 4.5"

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Old 12-24-2012, 08:08 PM
  #130
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Default RE: Shrike 40 with thinner airfoil

Making some good progress on my Shrike. It will probably be ready to go on the coldest day of the winter. Burrrrrrrrrrrrr!

I decided not to sheet with 3/32" and am pleased with deciding to step down to 1/16" for the full wing and stab areas. Pics are lookin good!

It is Christmas eve and I just came upstairs to post these pictures and while I am typing there are 7 whitetails feeding under the wild cherry trees in my front yard. They eat everything and have killed all my bushes on the east side of my house. I have no problem with that. Wild turkeys frequent my yard also. They are awesome birds. I counted 27 of them in my front yard yesterday.

I think they know I am cooking a ham for Christmas!

Merry Christmas!
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Old 12-24-2012, 08:21 PM
  #131
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Default RE: Shrike 40 with thinner airfoil

Lookin GOOD Speedy..!
Man..I'd love to have that many wild turkeys, that's amazing. Same goes for feral hogs...would love to have that "problem" too......!!
Merry Xmas and have a speedy new year.
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Old 12-24-2012, 08:38 PM
  #132
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Default RE: Shrike 40 with thinner airfoil

Here is a picture that I took from my home office window one afternoon late this fall.

I have to remember to turn off the "flash" on my camera or it scares the **** out of them.

They won't come back for a few days when I don't.
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Old 12-24-2012, 09:18 PM
  #133
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Default RE: Shrike 40 with thinner airfoil


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ORIGINAL: Speedy-Gonzales

Here is a picture that I took from my home office window one afternoon late this fall.

I have to remember to turn off the ''flash'' on my camera or it scares the **** out of them.

They won't come back for a few days when I don't.
Amazing. I wonder if there's a way to pick 1 or 2 of them off without scaring the rest of them away for good..?
We don't have much wildlife out here, nothing in any abundance. Rabbits would probably be #1 as far as edibles are concerned.
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Old 12-24-2012, 09:23 PM
  #134
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Default RE: Shrike 40 with thinner airfoil

SG, I dodge those guys crossing the continental divide on my way to work.
Sometimes a black bear gets in the way too.
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Old 12-25-2012, 05:06 PM
  #135
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Default RE: Shrike 40 with thinner airfoil

Looking good SpeedyG!
I think you will be happy with the weight you saved vs using 3/32, and the strength should be more than adequate.
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Old 12-25-2012, 05:46 PM
  #136
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Default RE: Shrike 40 with thinner airfoil

Hey guys...help me make a decision here?

Balsarite with Ultracote ( I refuse to use Monokote ) or 3/4 oz cloth and resin and paint?

Personally I think I will save some weight with the iron on.

Balsarite gives far better adhesion with iron-on and less chance of shedding the covering.

Resin,cloth, and paint is always heavier and no "warts".

Gentlemen ...place your votes!
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Old 12-25-2012, 06:14 PM
  #137
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Default RE: Shrike 40 with thinner airfoil

It's a tough call because you've got areas around the pipe where iron on film would suck.
You could do as much as possible with film, then scotch pad the edges of the film for overlapping primer and paint. Use 2 part [catalyst type] primer and paint if you want the most durable results.
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Old 12-25-2012, 06:22 PM
  #138
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Default RE: Shrike 40 with thinner airfoil

The front part of the wing/ fuselage has a fiberglass strip for strength. I feathered that area out with light spackle then used balsa rite and used monokote over it with very good results. Balsarite is only critical in areas with spackle IMO.
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Old 12-25-2012, 06:26 PM
  #139
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Default RE: Shrike 40 with thinner airfoil

I was planning on using "Flight metal" around the pipe area.

I have never incorporated the FG strip on the forward area where the wing meets the fuselage on any of my Shrikes. I have found it to be unnecessary.

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Old 12-26-2012, 03:36 AM
  #140
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Default RE: Shrike 40 with thinner airfoil

Glass and paint would be heavy for a performance plane but would come out looking about the best. I avoid plastic covering because I am not good at it.
On my SD I am planing on using tissue and dope over the sheathing.
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Old 12-26-2012, 07:18 PM
  #141
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Default RE: Shrike 40 with thinner airfoil

EZEKOTE is a water based urethane substitute to using epoxy resins such as Z-Poxy. I have seen it demonstrated at TOLEDO 2012 last April and was impressed with the application and lesser weight than epoxy resins. $20 for 500 ml

I have since found out that EZEKOTE is the same as a product sold by LOWES called VARATHANE. $48 for 1 gallon!

http://www.lowes.com/pd_49702-90-000...ane&facetInfo=

Varathene ( Ezekote) once dried is compatable with most paints.

http://www.youtube.com/watch?v=XQJ-mkoYQIo

I also could get in the "Wayback Machine" and go with silk and dope. Then primer and paint.

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Old 12-26-2012, 10:34 PM
  #142
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Default RE: Shrike 40 with thinner airfoil

I have seen some nice work done with water based varnish and polyester.
Carbon fiber veil applied with dope is an interesting alternative.
The veil is essentially tissue paper made with carbon fiber when bonded and finished with dope over sheathing gives you strength, a nice finish and is very lightweight (if your careful). The end product has the look and feel of fiberglass gel coated structure.
Tissue and dope over sheathing comes out pretty nice but is a bit of work.
Silk and dope is something I still do. lol
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Old 12-27-2012, 04:06 PM
  #143
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Default RE: Shrike 40 with thinner airfoil

Iron Eagel.....good to know there are stilll a few of us old "Dopers" out there.

Silk and Dope sounds very attractive at this point. Ounce for ounce silk is still stronger that FG cloth, very fine weave that fills easily over fully sheeted structure and conforms to rounded edges perfectly. I have been using silk for over 40 years. Very easy to apply AND if you are going to primer and paint over it you do not have to worry about blushing in cold weather. I can remember many times applying silk and dope in sub freezing temps in a cold garage with no problems and no blushing with humidity low.

" Once a Doper....Always a Doper!"

You gotta love this hobby!!!!
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Old 12-27-2012, 04:28 PM
  #144
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Default RE: Shrike 40 with thinner airfoil

Whichever method is chosen, I'd rather have the plane fly stupendously fast for just 6 months, then need to be retired VS choosing a heavier covering method that only allows second rate performance, even if it lasts for 20 years.
I mainly use $6.99 Towerkote, thinking that it is tough enough to get a day's worth of clockings over a rough hay field and actually it is good enough for much more than that most of the time.
I see a speed plane as a "delivery system" for my engine and prop..not a museum piece...but there can be a "happy medium" somewhere that allows some expectations of enough longevity to satisfy me long enough until the "next project" is due to commence.
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Old 12-27-2012, 04:33 PM
  #145
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Default RE: Shrike 40 with thinner airfoil

Just a short time back one fine scale "old timer" modeler from down south who doesn't use retarder offered a simple effective solution to "blushing". Just Spray thinner over the blushed paint, the blush instantly disappears. I tried it and it works, I would have never thought of that...
Silk is about the strongest and lightest method of covering/finishing out there, with the exceptions of tissue and carbon fiber veil. One of the problems most people have with dope and silk is it coming out to heavy because the supersaturate the silk with paint. The downside of the CF veil is that it has to go over a solid surface such as sheathing. One thing I am thinking of trying in the near future is covering a open bay structure instead of silk is to use tissue and after it is shrunk and doped apply a layer of CF veil at 0.2 oz/ square yard it's very light and adds a lot of strength.
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Old 12-27-2012, 04:38 PM
  #146
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Default RE: Shrike 40 with thinner airfoil

CP your one of the few people who truly "gets it". If your going for performance there are certain criteria you have to observe.

Heck a lot of guys think weight is a key to flying in wind, when the real factor governing "penetration" is power and thrust.
But a brick does fall faster than a feather....
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Old 12-27-2012, 05:30 PM
  #147
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Default RE: Shrike 40 with thinner airfoil

CBP does have a very good point though.

I want my Shrike to last longer than "a few passes" but I do have some pride in appearance too.

Iron-on is simple and all you have to do is remember to put clear tape overlapping the seams on all leading edges. I would not even consider putting up a 150 mph flight without clear tape on the leading edges.

Silk is easy to apply BUT the finishing process with primer,paint,and trim, is tedious. FG & resin is the same.

Decisions.....decisions....decisions!

My last 3 speed planes (Shrikes and Demons) and ALL my Q500's were/are Ultracote.

Me thinks "The Pigg" has touched a nerve....my brain is beginning to tingle!
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Old 12-27-2012, 06:06 PM
  #148
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Default RE: Shrike 40 with thinner airfoil

CP always looks at the the most practical considerations. "Whichever method is chosen, I'd rather have the plane fly stupendously fast for just 6 months, then need to be retired VS choosing a heavier covering method that only allows second rate performance, even if it lasts for 20 years. "
This is something that has to be a major consideration!
There is a old saying in aviation that goes something like this, if it isn't prop, motor, fuel or wings it's baggage!
My major problem with plastic covering is that I really "inhale sharply" at it.
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Old 12-27-2012, 06:34 PM
  #149
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Default RE: Shrike 40 with thinner airfoil

Breath in and sigh......................

My dear old Dad had a great saying.......ready?

"The only difference between rape and seduction is salesmanship"

I have a feeling you and CBP were/are great salesman !

I am going with Iron-on and Flightmetal under the pipe area.

Thanks guys!!

SG
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Old 12-29-2012, 08:01 AM
  #150
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Default RE: Shrike 40 with thinner airfoil

speedracerntrixie,

What airplane do you have pictured? That looks cool!
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