A friend of mine gave me a kit that he has had for a long time... it is a Great Planes Deception, NIB. He lost an eye and was forced out of the hobby years ago, and I guess he was house cleaning. Does anyone know anything about the finished product? Is it worth building? I have a lot of scratch building experience, so putting it together is not a big deal, but it sure has a lot of blocks to carve! It is set up in the plans for tricycle and a tuned pipe (which I also have) ... is it standard practice in classic pattern to build these ships this way, or convert to tail dragger?
Any info would be appreciated -- my friend seemed to think that this design was a very good one.

LF-
You have a fine classic pattern kit and it sounds as if you can do it justice. I recommend you build it per plans, 2-stroke w/pipe and trike gear.
-Ron

They fly like real pigs, what you need to do is pack it up and ship it to me, I will dispose of it properly for you. LOL

Just kidding these are great flying birds, congrats on the great find.I wish I had some friends like that. LOL

I built two Deceptions in the early 80's and used them in competition from '81-'85. I loved them both. I lost one to a mid-air and flat wore the other one out. I am, in fact, planning to build another from plans since the kits have become scarce. I second Grotto2's opinion - trike gear and a piped 60. At various times I used a Super Tigre, then several Webra Speeds, and then a Rossi on mine. If you decide not to build the kit, please let me know. I'd be interested.

Jeff

Does the GP kit differ much, if any, from the MAN plans?

The reason I ask is that the MAN plans show an unusual, transitioning airfoil from root to tip. I'm wondering if the GP wing is like this.

Based on what Rich Ernst down in Florida has experienced, you're gonna enjoy that DECEPTION. I was fortunate enough to
see Rich fly his at the SPA Masters contest this year in Hotlanta, GA. Nice performer.

Here's a link to the SPA newletter of MAR/APR 2006 that had a feature on Rich and his DECEPTION. Check it out.

http://www.seniorpattern.com/newsletter/MarApr06.pdf


His e-mail address, if you need to get in touch with him is:

[email protected]

Good luck on your' project. Hope this has been a help. Best Wishes,

Bruce Underwood SPA # 15 Guntersville, AL
[email protected]

Why is that unusual, David? Lots of pattern planes use different root and tip airfoils, with foam wings the transition is automatically built in, too.


Mark

I guess I've seen a lot more examples where the thickness transitioned, but not as many examples of the airfoil type changing. I have seen some other examples in the plans I have, but the number is fewer than the more typical thickness changes one sees. I'm obviously basing that on what I've seen (I think the Compensator is another example of an airfoil transition similar to the Deception).

Thanks for the kind words, Bruce. I built my current Deception from a Bridi kit and modified it specifically for SPA events. The engine is on OS91 Surpass IIP with stock muffler. The taildragger landing gear is a Bolly F3A unit bolted to the fuse just in front of the wing with aft facing taper. The rudder and elevator servos were moved aft to balance out the heavier engine and of course dual aileron servos were used. Covered in Monocote, it feels about the same as my older Webra piped, retract Deception.

Flying style is totally different. I'm using an APC 13/9 prop and getting about 9500 rpm on 30% heli fuel. The plane flies at slower, more constant speed and with much more vertical capability. It's balanced for a very, very slight down elevator at inverted. Knife edge is improved.

Now if only I can learn how to fly again, it'll be a winner.

Rich Ernst
[email protected]

teamvortex, very nice story and article. That's a beautiful model.

LOved my Deceptions (all 6 of them). I built 2 from the Bridi kit and 4 from scratch (MAN plans). I seem to remember that Bridi plans showed too much dihedral and the MAN plans were correct (something like the center section 1/2" above a flat surface with the wing upside down). Also, I always built the rudder full length (not stopping at the stab). Otherwise, a great flying plane.
ENJOY,
Will B.

Wow -- what a response! Thanks for all the advice, all of you.
With regards to the airfoil, I dragged the Deception kit out from under the Midwest Giles 202 kit, the Cap 232 kit, and the Wing P-39 kit, and shoved the ZP-38 over to the side of the bench (I just gotta quit this job ... it is really getting in the way of important work), and looked the wing over. It is exactly as you drew it above, and I have to say that the Great Planes foam cutting was very good. The kit shows it piped through a fiberglas canopy shroud, with the engine upright (pretty darned ugly). My benefactor also gave me an Irvine 60 rear exhaust, the pipe and couplers, but I am not sure my club will be all that happy with the noise. I've never used a tuned pipe before, but I understand that they are very loud -- maybe one of you can comment on the noise factor.

I can't sell this kit -- the person who gave it to me wants to see ME flying it, and I can't let him down. However, I took the opportunity to look the kit over since there seems to be a number of you who would want one (I got a bunch of private email with offers to buy it ... I did not know what I had). I wanted to see how hard it would be to clone the kit from the parts. Obviously, the wing is easy, but I figured there must be a lot of bulkheads and cut parts that could be cloned to make short kits. What is actually in there are a very few bulkheads, the firewall is from 1/2" ply (?!), and an entire tree of various blocks, triangle stock, and sheet goods. The blocks alone make up 30% of the area in the box. So ... since you could get a wing core from a vendor, aside from the plans, I am not certain I could add a lot of value by cloning the cut components. However, if there is anyone out there who is interested in me giving this a shot, shoot me an email. I have lots of foam, and could cut the wings, copy the plans, and cut out those parts that matter. I guess I could also buy all those blocks and sheets too, but you could do as well buying that stuff online. If five of you want one, I'll take the plunge! Since you don't know me from Adam, the terms would be money back if not satisfied. And no, I do not have the foggiest idea of price - if there is sufficient interest, I'll do the cost breakdown and we'll all decide if we should proceed.

Regards

There was a streak of ugly that occurred in the evolution of aircraft around that time with pipes going across the fuselage tops. A couple of years later some GENIUS realized that planes would be better balanced and run cleaner with inverted engines....and that has stood ever since.

As far as the noise goes, you can probably cut down a lot by using a Hatori 650, 601 or similar muffled pipe and an APC prop without any sacrifice in speed. A fibre mount will also be a little soft and suppress a bit of noise, too.

I'm not sure if your Irvine pipe is muffled. If it looks like two cones welded together it is not. If the rear section is cylindrical or rounded off it is and you can give it a shot instead of buying a Hatori.

Thank you sir! I'll look the pipe over against your specs. I think the way to get her looking the best is to go inverted, as you say, and fom a glas cowl instead of the wood blocks.

This is an old perception from the days of screaming open piped engines. Current pattern aircraft still run tuned pipes on the 2 strokes and they are among the quietest aircraft you will find. If you have an open pipe (look at the Mac's Products site for the various pipe types - http://www.macspro.com/tunedpipes.asp ), then it will have a pretty sharp crackle to it. But a muffled tuned pipe is not at all loud. Second source of major noise is the propellor. The old pattern ships also screamed because of running medium pitch props at very high RPM (11x7 prop @ 15,000+rpm was typical) to generate speed. You can reduce much of that by running higher pitch props at lower rpm to get the speed. Also, APC props are much quieter than the older designs of the 70's and 80's, at any given rpm. The combination of quiet tuned pipe, higher pitch prop, lower rpm and better props will let you run a screaming fast pattern plane without offending the neighbors. Basically, you want a setup from just before turnaround or the early turnaround period for fast and quiet.


Mark

I agree with the higher pitch APC props being quiet. I've been bench running an 11x10 (11,250) and an 11x11 (10,250) on my .61 and it's not really offensive at all. In fact, the next door neighbor was in her front yard and said she hardly even notice it running when I asked if it bothered her.

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


Even the Bridi version that I butchered (built) and managed to get flying, did handle very well. A beautiful model with good, traditional lines. If a real one had been built, it would have been built by Republic Aircraft, manufacturer of the P-47.


Ed Cregger

Here's an old shot of two Deceptions setup with side and rear exhaust
engines. I liked the side exhaust setup myself. This is a great flying plane.

Ron

Since there's a full fledged Deception thread going here, can anyone give a bit of history on the design and designer? Why the name? (I always thought it had a deceptively DBish look to it)

Rainedave,

Deception was designed and built by Jim Kimbro in California while he was working for Phil Kraft. As part of my SPA validation quest, I located and contacted Jim and got the note that he first flew it on November 1975. The MAN article appeared in the 9/78 issue and is still available on e-bay from time to time. Jim flew his with side exhaust Rossis on a pipe. Why he called it Deception, I don't know. By the way, Jim recommended that the rudder not be extended to the bottom of the fuselage. The upper only design redcued the yaw-roll cuouple that pattern planes had back then. Mine is as per Jim's design and knife edges with no yaw-roll issues to trim out. Remember, we had no computer radios back then to overcome design defects.

The rear exhaust version is UGLY. The canopy in the photos is also used on the Bridi Escape from early turnaround days. I'm building one of these also with a backdoor Rossi.

The dihedral on the Bridi plans is wrong.

Jim is currently getting back into pattern. He and his family still live in California.

Rich
TeamVortex
Brooksville, FL

The noise comments are right on target. My plane with the OS91 and 9000 - 10000 on the APC 11/9 is extremely quiet.

I, too, thought that the Bridi kit called for too much dihedral. When I was in California on a business trip in the early 80's I had the opportunity to meet Joe Bridi and I asked him about it. He replied that Jim Kimbro (the designer) had made the modification to the dihedral that Joe incorporated into the kit. Nevertheless, if you use the rudder as designed (the movable portion only extends down to the top of the fuselage) I still feel that the kit dihedral is too great. That was how I built my first one. My second had the movable portion extended all the way to the bottom of the fuselage to get more rudder authority and to lower the center of pressure on the rudder. If one were to do this, then there would be less adverse roll induced by the rudder deflection and the amount of dihedral should definitely be reduced. Dihedral will result in a roll in the direction the rudder is deflected. A rudder which has the center of pressure above the fuselage will result in a roll opposite the direction of deflection. Dihedral should be balanced against the adverse roll induced by the rudder. There are other considerations, of course, but this is certainly one. Back then I asked Don Lowe about this situation since he has a background in aerodynamics. His repsonse was that it was simple to take an electric saw and cut through the top of the wing center section, adjust the dihedral, and put an epoxy bandage over the cut. That way you could slice and dice and adjust the dihedral all you wanted. That was how he dialed in the correct amount on some of his designs. But, I never could bring myself to cut the wing on a successfully flying model. Not enough engineer in me, I guess (actually I am a theoretical physicist).

Jeff

Jeff,

Nice summary. However, I built it with the "short" rudder and the lower dihedral and it doesn't have any coupling issues that I can find. Agine the real world vs. aerodynamic theory.

(BTW, I've got two degrees in aero from Georgia Tech and this is far from the first time I've had results not quite in line with my "very carefully and accurate" calculations (g))

I've also cut wings like Don suggested. This was one of the tuning techniques in the "good old days".

threads like this are what's fun....

Rich

Since I have a copy of the MAN plans, I thought I'd post the dihedral detail.

Rich,

That's good to hear about how yours turned out. I am still waiting for the MAN plans ("any day now") and I was debating which rudder configuration to use. Now I am leaning towards the standard rudder and the original dihedral called out on the MAN plans as yours has worked out well. Back when I built mine as per the kit the dihedral on #1 was too great even with the short rudder. I built the second with the lengthened rudder but I hadn't thought through the dihedral issue fully. As I recall, I did reduce it some, but not enough. Now it seems as if the original dihedral (not the kit) combined with the short rudder was the correct amount to begin with. Ah - if only I had a time machine...

Jeff

Hi LightningFann,
The piped 60 can be made to be the quietest thing in the air. With a pipe length of something like 16"~18" from glo-plug to baffle and an 11-11 prop you will have the fastest plane around, and darned quiet.

best of luck,
Dean Pappas