stunthanger.com
Classic Designs => Classic Planes => Topic started by: Wynn Robins on September 22, 2008, 06:27:04 PM
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Looking for plans for a classic legal twin - anything considered
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L A Heat, by Bb Whitley should do the trick......
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How about the "Two Bits" centerline thrust twin (1967) that showed up at VSC last year...
I think Jack Sheeks "Skyrocket" is also classic legal.
The LA Heat is a Classy, but not "Classic Legal". RSM lists it among their "Modern" (not their classic line) and they point out it was top 10 1987 NATs.
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LA Heat was sixth after Bob himself coached Kaz Minato on a maneuver and Kaz ended up beating him the next day. Great story of sportmanship.
Chris...
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How about Tuptkers Fokker D-23 .
Two injuns , We have the Tecnology !
Another N.Z. First ?
Apparantly the Americans havnt heard of Pearse .
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Twin Flite Streak.
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Jack Sheeks AT-9
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I'd vote for Two Bits. It's just cool.
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Tom Niebuhr suggested a 2 Veco Mustang kits with a constant chord wing segment between the tapered outboard halves.
So cool, I wanna build one!
Chris...
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Tom Niebuhr suggested a 2 Veco Mustang kits with a constant chord wing segment between the tapered outboard halves.
So cool, I wanna build one!
Given the NAME of this place, if you were really going to use any smaller size Mustang design as the basis, choose the thicker winged Kenhi Mustang instead (same designer, Hi Johnson, two years or so newer), or something still newer yet, such as the RSM profile kit (you could develop a built-up fuselage for it without great difficulty).
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>>...such as the RSM profile kit (you could develop a built-up fuselage for it without great difficulty).<<<
Or, you could just contact Pat Johnston. I'm sure he could draw up his Mustang (a killer plane, by the way) as an F-82
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As nice a plane as the F-82, as designed by Pat might be, it still would not be a classic legal twin. There are precious few that are, and as far as I can tell, they all have been mentioned in this thread.
Now, if you just want a twin stunter, there's a lot to be said for the concept. Pick your subject, and remember a few axioms. Things that always work as Bob Whitely says.
The nacelle legnth only needs to be long enough to hold the engine, and enough fuel to fly the pattern.
The tail needs to be long enough to balance out the weight of two engines, and their fuel tanks.
You should figure about 2 inches of clearance between the prop tips, and the fuselage.
Most who desire to design a twin, over power them. a pair of decent .20's will carry about 700 sq inches without hardly a problem. A pair of hot .15's will power a 620 sq inch plane.
Make sure there is no in-thrust in either engine.
Set the inboard engiines thrust line straight ahead, while giving the outboard engine a slight, 1 to 3 degrees of out-thrust.
Bob's things that always work should be imployed. A slight amount of down thrust is good, about 2 degrees plus or minus. along with a slight amount of positive incidence to the stab, will really help the plane fly well.
Properly rigging a twin is a more difficult procedure than most realize. Gordan Delaney has shown me that setting, and fixing the wing at 0-0 is the first step.
Next, set the nacells with the thrust line incidence where you have decided it should be. Make both thrust lines the same, as far as down thrust is concerrned.
Install the fuselage square to the wing.
Lastly, install the stab square to the wing. Make sure the distance from the flap hingeline, to the elevator hingeline, is equal, both sides of the fuselage.
Given a choice, simplify the control system, by mounting the bellcrank outboard when delaing with twin boomed, or double fuselaged designs. (P-38 and F-82 are good representatives of these styles.) The flaps and elevators will need to be stiffened up to resist twisting under heavy load, but it's not too difficult a task with todays materials.
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Given the NAME of this place, if you were really going to use any smaller size Mustang design as the basis, choose the thicker winged Kenhi Mustang instead (same designer, Hi Johnson, two years or so newer), or something still newer yet, such as the RSM profile kit (you could develop a built-up fuselage for it without great difficulty).
Wanted to keep it Classic of course, but the Kenhi would be a choice also.
I flew both of Bob Whitely's and they didn't fly that much differently, except the Veco was more consistent. Bob liked the Kenhi less than the Veco, kept the Veco and gave the Kenhi to my youngest son.
It is now my Old Timer, just good enough for my Old Time skills.
Chris...
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I flew both of Bob Whitely's and they didn't fly that much differently, except the Veco was more consistent. Bob liked the Kenhi less than the Veco, kept the Veco and gave the Kenhi to my youngest son.
It is now my Old Timer, just good enough for my Old Time skills.
I am surprised that the Kenhi kit design could qualify, since I didn't think Johnson and his partner had started their company until after 1952 was over with. Admittedly, in 1952 I was more likely to look at an Enterprise or Scientific kit advertisement than either Veco or Kenhi (except the Papoose, since I did have a .19 back then).
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The Veco was 1948 and the Kenhi was 1950, I think.
Chris...
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Tom Niebuhr suggested a 2 Veco Mustang kits with a constant chord wing segment between the tapered outboard halves.
So cool, I wanna build one!
Chris...
While I think twins are neat, this was not my suggestion. I can't think of any more Classic twins than those already mentioned
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An interesting item to note on the "Two Bits" at VSC this year, is the interesting fix applied by Whitely for some engine run problems. They surmised that the rear prop, running in dirty air, was the culprit. They ran a different pitch on the two engines, and the plane flew and ran much better. Perhaps Bob will step in and run the facts, rather than my admittadly faulty memory, past us.
I've always liked tandem twins, I even have a design on the boards for one, but the fuel delivery problems that seem inherent to the rear engine, have held me back. I think the obvious solution, for this, and most regular twins, may just well be electric power.
A lot of variables would be gone with a good electric power package.
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Delgatto (Paul I think) B-25?
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There are two designs of the Two Much. Mark Fechner who designed the original twin. It had lines like the Nobler with a deep fuse. It also had longer nose momments.When I built mine I shorten the noses 1inch.and lengthen the tail momment 1 1/2 inches,and slimed down the fuse alot. move the canopy forward two inches. It help the design alot. It won several contest in it`s day.
Gordy
PS. And it is classic legal. Marks was test flown March 1962.
Mine was built in 1966 and flew it`s first contest in Buckeye Az. 1967
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How about the "Two Bits" centerline thrust twin (1967) that showed up at VSC last year...
Rick Loomis re-drew and built his latest Two Bits all over again in 2007. I think he had Eric Rule laser cut the ribs, which I believe are Palmer Thunderbird. It has two Aero Tiger 36's and weighs a good bit but not excessive. Bob flew it at VSC '08.
I flew it at the Palmer Classic at Whittier Narrows, CA in '08. The practice was a thrash and eventually the model was withdrawn for technical issues. Later found to be a battery lead problem!
The airplane flies very well, doesn't pull too hard yet is "right there" all the time, never gets loose. Turns well, very docile and easy to fly accurately. Even with three flights I was confident enough to enter the contest with it.
Worth a look.
Chris...
Pics are of Bob helping get 'er going at Whittier.
Second is of me flying it. See, I'm not all bent over!
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Jack Sheeks Mosquito.
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Would the little .049 Skyrocket ,scaled up, be classic legal ?
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Jack Sheeks Mosquito.
Unless Jack can come forward and say that his Mosquito was designed prior to the December 1969 Classic cutoff date, his Mosquito is not classic legal. It was published in the August 1981 issue of Model Aviation.
Keith
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Would the little .049 Skyrocket ,scaled up, be classic legal ?
No
Keith
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Jack Sheeks AT-9
Unless Jack can come forward and say that his AT-9 was designed prior to the December 1969 Classic cutoff date, his AT-9 is not classic legal. It was published in the August 1976 issue of Flying Models.
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(clip)
I think Jack Sheeks "Skyrocket" is also classic legal.
Jack's Grumman F5F-1 Skyrocket was published in the Aug/Sep 64 issue of flying Models = Classic legal. (Lots of wing area. Should work pretty good.)
Keith
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How about Tuptkers Fokker D-23 .
Two injuns , We have the Tecnology !
Another N.Z. First ?
Apparantly the Americans havnt heard of Pearse .
The "push-pull" Fokker D-23 by Dick Sarpolus was published in the December 1976 issue of Model Aviation. Unless Dick or somebody can verify that this was designed prior to the Classic cutoff date, is not Classic legal.
Keith
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Delgatto (Paul I think) B-25?
Paul DelGatto had his B-25 publsihed in the Feb/Mar 63 issue of Flying Models. It was designed for CL stunt with a decent thick symmetrical airfoil. Leroy Black campaigned one for several years, including several times at VSC. With Leroy, it flew a "respectable" pattern. I am not sure what engines he used.
Keith
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I am not sure what engines he used.
2 x OS .25LA
mk
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Cool! I never got to see that one.
Chris...
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Remember to include Lew McFarland's P-38 in your search, and I swear I remember that somebody had an F8F Tigercat, but I can't remember who, and my computer with the Stunt Bibliography is down just now.
Ralph
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Remember to include Lew McFarland's P-38 in your search, and I swear I remember that somebody had an F8F Tigercat, but I can't remember who, and my computer with the Stunt Bibliography is down just now.
Ralph
Lew McFarland's P-38 was published in the Sep/Oct 66 issue of American Modeler = Classic legal
An F8F Tigercat might be hard to find. The F7F Tigercat is the twin engined fighter. Other than several designs that have been published for carrier and a really small CL scale model in the late 40's, I am not aware of any design for the Tigercat that might be Classic legal. Windy had a very nice, to his normal impressive standard, Tigercat at the Nats several years ago, but it would hardly be Classic legal. It flies very well. There were plans for a scale CL version of the F7F available from Paul Plecan with a copyright date of 1951. Chris McMillin built one of these for VSC in 2007 to fly in OTS. It was thought that with its fairly decent airfoil and if built light enough and with adequate power, it would be able to do the OTS pattern. Unfortunately, it appeared to be somewhat OTS pattern challenged. I will let Chris elaborate. Bob Whitely also built a scale P-38 from another Paul Plecan drawing for VSC in 2007 that was OTS legal. The same thinking went into this model as well that it would be able to get through the OTS pattern. It too proved to be somewhat OTS pattern challenged. Both were great looking airplanes and a lot of pictures of these two airplanes were publsihed after that VSC.
Keith
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Paul Tuptkers D-23 was built as a single engine device, which he is aledged to have stated flew better than his Grondal Nobler,in the "Aeromodeller " magazine ( British ) .
There was one small artical with a scale drawing, another month it had pictures and more spiel,
Somewhere stating "with twin wengines ", blah , blah, regarding engine Wt.
Does this make it , if dates are O.K. , legit twn engined ?
Have the thing drawn up here somewhere from the little published drawing.
Best with a shaft drive to the rear prop, similar to a Stilletto 1/4 A Proto Speed -set up ?
If anyones seen the photo of the D-23 and likes it enough to build it ,I will send them the drawing (full size ) .
About 54 in span,Bellcrank mounted at outer tailboom.
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nd . . .
Was al;so a profle Invader published . Thin wing . No Flaps.
Anthing published on the "Two - Bits " push-pull ?
Now, theres a sovia S-65 push pull float plane . . . .
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The Paul Plecan F7F Tigercat was brought to my attention by Keith in 2005 or 06. The plan was for Bob Whitely, Keith and myself to build them and have a three ship. Never happened but I finished mine in 2007 and flew it in OTS. If it weighed 30-32 oz it will probably fly the OTS pattern. Mine weighed 45 with 6 oz of lead in the nose. I could build one to 30 oz if I did it again.
The way to do it is use a lost foam wing, tail and vertical, molded fuse and nacelles, and the little OS 15 FP's were still plenty at 45 oz.
Whitely's Lightning was the same deal, too little wing for the weight, extraordinary weight control needed during construction.
Chris...
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Lew McFarland's P-38 was published in the Sep/Oct 66 issue of American Modeler = Classic legal
An F8F Tigercat might be hard to find. The F7F Tigercat is the twin engined fighter.
Keith
Thanks for the correction, Keith. I'm sure I wanted to type F7F. Sometimes there's an eye-hand problem . . .
Ralph
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Ralph,
...Looking into this one a bit late, but there was another F7F Classic-eligible design. A smallish profile, kitted or published during the Classic era. It may be the same one that Brodak now kits...
In at least two, possibly three VSC, Jim Hoffman flew one he'd built from plans. ASIR, 2 X OS 15 FP, bladder pressure with a specially built metering gizmo. Thin airfoil and complicated power system... Fast, turned large, but Jim is an excellent flier and got the most out of it.
Further thoughts: Jack's F5F had the "feel" of the original's looks, with (of course) a "few" rationalizations for stunt. He chose a fuselage nose that went forward of the LE, and sort of resembled the XP-50, Air Corps tri-gear version more than the one or two US Navy prototypes. The first XF5F had the nose snubbed at about 1/3 chord back from the LE. A later Navy variant had it forward of the LE, but squarer looking than the XP-50's nose - which looked very much like the later F7F (non-recon) nose.
That "Hawk Squadron" F5F original tempts me occasionally to think about Jack's Skyrocket, but I'd be happier with the snub nose, and possibly dihedral in the stab-elev. ...Doubt anyone built one that way within the Classic era... Aw, shucks...
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There is an auction on e-Bay for plans for an F-82 twin profile stunter from 1968. The original had Johnson 35's so it appears that it is a pretty big airplane. Item number is 250298831630.
Steve
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Ralph,
...Looking into this one a bit late, but there was another F7F Classic-eligible design. A smallish profile, kitted or published during the Classic era. It may be the same one that Brodak now kits...
In at least two, possibly three VSC, Jim Hoffman flew one he'd built from plans. ASIR, 2 X OS 15 FP, bladder pressure with a specially built metering gizmo. Thin airfoil and complicated power system... Fast, turned large, but Jim is an excellent flier and got the most out of it.
Further thoughts: Jack's F5F had the "feel" of the original's looks, with (of course) a "few" rationalizations for stunt. He chose a fuselage nose that went forward of the LE, and sort of resembled the XP-50, Air Corps tri-gear version more than the one or two US Navy prototypes. The first XF5F had the nose snubbed at about 1/3 chord back from the LE. A later Navy variant had it forward of the LE, but squarer looking than the XP-50's nose - which looked very much like the later F7F (non-recon) nose.
That "Hawk Squadron" F5F original tempts me occasionally to think about Jack's Skyrocket, but I'd be happier with the snub nose, and possibly dihedral in the stab-elev. ...Doubt anyone built one that way within the Classic era... Aw, shucks...
Lou,
Why do you doubt someone didn't build it that way in the Classic era? Why wouldn't they?
Build it the way you want and let the knit pickers that haven't built a model in 30 years complain, so what!!!
Chris...
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I think Chris is on to something.
The fact is that when people built either kits or plans in the Classic era they often added their own special touches. The slight dihedral into the stab would be no big deal. Someone could have easily shortened the nose or the nacelles to make Jack's published design look a little different. Extend the nose and make it a trike and you (working from Jack's plans) could easily turn it into the US Army XP-50.
Would it be ACCURATE to the published design - not really. Would the mods Chris or I described be representative of the Classic era (dare I say it) YOU BETCHA! #^
Edited: pix added shoing three slightly different versions of the Grumman XF5F, F5F & XP-50
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Just look at how many "Nobler" wings were put into so called original designs. DOC Holliday
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Ty, Dennis and Chris,
I wasn't thinking that NO ONE had done a Hawk-a-a-a-a!! version, just that it most likely couldn't be documented as from the Classic era. I'd prefer if it could have been.
Another "rationalization" for stunt with a pair of Fox 35's was the (Sterling Nieuport 28?) turned metal cowls. They were available, then, and looked good. They are quite a bit smaller than would have looked closer to scale. With 11" and 12" props, flat pitch, on more recent engines, a larger cowl should be no penalty.
As for kit bashing "back then"... I was there, too. ...Don't think I ever built anything true to the mag article photos, kit box or cover art until OT and Classic got going. Part of appearance judging included (...at least the idea of...) originality.
Youze gize is temtin mee...
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Lou:
u-da-man! GO FOR IT! H^^
You called it: Jack's is the second or modified Navy version with the lengthened but boxy snout and the lengthened (back end) nacelles. Personally, I like either "extreme" version: either the original snub nose with short nacelles, or the stretched-out XP-50 trike. As for the V in the stab, you don't have to ask ME about that! 8)
Oh yeah, ELECTRIC would be so easy its almost cheatin...!
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Gosh,
I feel like I'm cheatin' when I'm using an electric starter.
Chris...
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Lou:
u-da-man! GO FOR IT! H^^
You called it: Jack's is the second or modified Navy version with the lengthened but boxy snout and the lengthened (back end) nacelles. Personally, I like either "extreme" version: either the original snub nose with short nacelles, or the stretched-out XP-50 trike. As for the V in the stab, you don't have to ask ME about that! 8)
Oh yeah, ELECTRIC would be so easy its almost cheatin...!
Trouble with the XP-50 is it caught fire on it's maiden flight and was lost. You would have to replicate that event every time you flew :)
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Twin Flite Streak.
Does anyone have more info on the twin flight streak?
Did it use flaps?
Plans available?
TIA, H^^
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Hey Rudy, I have the plans, check my website. www.cadclassics.net look on the designs page towards the bottom. It doesn't use, or need flaps.
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Thanks John,
I just sent in my order for your plans. y1
Is there any chance you can produce a rough sketch you made of your beautiful Biplane design back in 1969? I am sure you must have something, a napkin sketch, an old model mag doodle you made in the margins, anything that would make it Classic legal? LL~
Regards, H^^
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I but I wish I had something doodled on the bipe back then. I only designed one plane back then. I was caught up in the idea of a Canard Stunter, and intrigued by the B-70 Valkrey. I came up with a set of plans for a pusher version as a stunt plane in '67.
I last saw that set of plans a few years ago. I neverf built it either. The way it was set up it would have some real modifications for it to ever fly well. It sure looked neat though.
Thanks for the order. I think you'll find the Twin F.S. a fun plane, and it flies pretty darned good. If you use a pair of OS .15 fp's tip the nitro to 20%. better is a pair of .20's on 10%.
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Hi John,
Thanks for your answers. Mine will have two Hackers for power. :-)
Do you remember the all up weight for the one with two .20s?
What is the area?
TIA
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electric will be great.
As I remember, the all up weight was mid 50 oz's. Area is 770 sq inches. H^^
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Not sure if anyone recognises these or knows if the plans are available.
(http://controlline.org.uk/phpBB2/files/jesus_saves_453.jpg)
Apparently taken at the NSW State Championships 1960, they are all designs by a guy called Neil Wymark, quite a character apparently. Full post on Barton club site. http://controlline.org.uk/phpBB2/viewtopic.php?t=4498
TTFN
John.