Author Topic: Walt Pyron p-39 (Read 4248 times)

roger gebhart · « **on:** January 12, 2015, 01:19:56 PM »

I'm trying to do better and finish a few projects started long ago. Wife says I have to or else.

So I have this basically framed up P-39 and am going to make it project #2. I have a fox 35 new and a brodak 25 new. Will the 25 suffice for this project? I am not thinking competition. Just fun. rog

Gerald Arana · « **Reply #1 on:** January 12, 2015, 01:24:17 PM »

I'd use the B-25.

Cheers, Jerry

Dennis Leonhardi · « **Reply #2 on:** January 12, 2015, 02:28:35 PM »

That's a real nice looking design - post pictures!

Dennis

Randy Cuberly · « **Reply #3 on:** January 12, 2015, 02:39:44 PM »

Isn't the Walt Pyron P-39 around 525 sq in with a built up fuselage?

Might be a bit much for the B 25 unless you dan build it really light.

The Fox is a good match in terms of weight and power.

Randy Cuberly

Bill Morell · « **Reply #4 on:** January 12, 2015, 02:51:13 PM »

Since it it "just for fun" put a .60 in it and you will have a handful of fun!

roger gebhart · « **Reply #5 on:** January 12, 2015, 03:35:03 PM »

Randy; Yes about 525 measures out pretty close. Full fuse with side mounted engine. Kinda why I was shying away from fox. I also have an OS 40fp if the B25 doesn't seem to be enough. I am however at a point where provisions need to be made for motor soon.

Jerry that is the choice I would prefer but don't want to end up weak on power.

Bill I don't have any .60 Maybe OS 56fs

I'm still listening

john e. holliday · « **Reply #6 on:** January 12, 2015, 03:40:52 PM »

The Brodak .25 should be enough power with a different venture and prop. They do need break in like the Brodak .40 I have discovered. Need to post pics of the plane so we can see it.

Clancy Arnold · « **Reply #7 on:** January 12, 2015, 04:08:11 PM »

Roger
I recommend the OS 40 FP! Twice the power of the Fox 35 and runs on readily available RC fuel.

Add a Throttle and have a ball.
Clancy

roger gebhart · « **Reply #8 on:** January 12, 2015, 04:25:27 PM »

OK there it is. Probably not really light. It's never been weighed at this point

wwwarbird · « **Reply #9 on:** January 12, 2015, 05:31:26 PM »

Roger,

Out of the options you've mentioned, go with the FP.40. The B25 might fly the model but unless the plane is a featherweight build you'll have no reserve power at all. The 56fs is much bigger and heavier than you need for this design, plain and simple. I've got a Pyron P-39 with a Fox .35 in it that performs very well but it's also built on the light side. The only reason it's got a Fox in it is because that's what the original builder had it set up for so that's what I replaced it with. Go with the FP, it will be a great match, and be a dependable runner.

roger gebhart · « **Reply #10 on:** January 12, 2015, 05:53:08 PM »

Wayne; looks like the 40fp will be the choice for this one so now the work begins. Thanks to all of you for the input.

wwwarbird · « **Reply #11 on:** January 12, 2015, 06:05:03 PM »

Sounds great Roger, keep us posted!

Dennis Leonhardi · « **Reply #12 on:** January 12, 2015, 08:58:30 PM »

I have a nice set of plans for this one, plus a copy of the construction article - $12.95 + S&H.

Walt also did a nice "Black Hawk", which strikes me as an updated version of Bob Elliot's "Black Tiger" (Berkeley P-40). The "Black Hawk" features swept trailing edge (much more resembles the P-40 wing), wing-mounted landing gear, bubble canopy replaces the turtledeck (as on later P-40 aircraft versions). Same deal on plans & article for that one.

Dennis

http://stores.ebay.com/airclassix

Balsa Butcher · « **Reply #13 on:** January 13, 2015, 04:23:41 PM »

Bob Hunt featured this design in is Classic Series articles published in the late, great Flying Models back in the 90's. Plans were re-drawn and updated for modern construction techniques. Anyone thinking of building one would be well advised to at least hunt (pun intentional) down the article for review before cutting any balsa.

roger gebhart · « **Reply #14 on:** January 13, 2015, 05:19:13 PM »

I have both and totally agree.

Larry Borden · « **Reply #15 on:** January 13, 2015, 07:27:36 PM »

Anyway to get a copy of Bob's article and plans?

John Leidle · « **Reply #16 on:** January 13, 2015, 07:49:29 PM »

Fp might be fine I think a TT .36 might be a tad lighter in the nose...

Larry Borden · « **Reply #17 on:** January 16, 2015, 10:04:54 AM »

Found the back issue of Flying Models on ebay.
Can't find the plans.

Balsa Butcher · « **Reply #18 on:** January 16, 2015, 10:22:33 AM »

Am I wrong here or is there a small copy of the re-drawn plans in the article? If so, that should suffice for the recommendations Bob makes. I think one dealt with the placement and mounting of the horiz stab. There were no changes that would make it less than qualified for Classic. I flew with Walt back in the 90's when this was published. He flew very precisely and fast, real old school. One of the greats.

roger gebhart · « **Reply #19 on:** January 16, 2015, 02:39:19 PM »

The redrawn plans are available on outerzone. They are listed as Walts original but they are the Bob Hunt redo. rog

roger gebhart · « **Reply #20 on:** January 19, 2015, 05:08:05 PM »

Quote from: wwwarbird on January 12, 2015, 05:31:26 PM

Roger,

Out of the options you've mentioned, go with the FP.40. The B25 might fly the model but unless the plane is a featherweight build you'll have no reserve power at all. The 56fs is much bigger and heavier than you need for this design, plain and simple. I've got a Pyron P-39 with a Fox .35 in it that performs very well but it's also built on the light side. The only reason it's got a Fox in it is because that's what the original builder had it set up for so that's what I replaced it with. Go with the FP, it will be a great match, and be a dependable runner.

Ok Wayne I should have been paying more attention. I have been studying the airplane to get a feel for where I really am with it. So I have decided to put morris controls in it. A little more work but I think worth it. Will also add a slider. Like Wayne said the airplane is set up for a fox 35 and it is short enough and narrow enough to install without redoing the nose. With that said the airplane is on a diet. Not going to drill it full of holes but will pay attention from this point forward. The engine is side mounted so should I do the mods to the fox that I have found here? That's about it for now so well see what else comes up from here. rog

wwwarbird · « **Reply #21 on:** January 19, 2015, 05:16:47 PM »

Quote from: roger gebhart on January 19, 2015, 05:08:05 PM

Ok Wayne I should have been paying more attention.

Huh???

Go with the FP Roger, like I explained above. Save the Fox for a Ringmaster.

roger gebhart · « **Reply #22 on:** January 19, 2015, 05:30:07 PM »

Wayne the firewall is already mounted, the beams are to narrow and the fp is about a half inch longer and quite a bit heavier. I'll look at it some more but seems like a lot of work at this point. $:-\$

wwwarbird · « **Reply #23 on:** January 19, 2015, 05:37:39 PM »

Quote from: roger gebhart on January 19, 2015, 05:30:07 PM

Wayne the firewall is already mounted, the beams are to narrow and the fp is about a half inch longer and quite a bit heavier. I'll look at it some more but seems like a lot of work at this point. $:-\$

Your call Roger, but it's easier to do a couple mods now rather than later.

roger gebhart · « **Reply #24 on:** January 19, 2015, 05:44:22 PM »

How much fuel for fp to get through pattern. (not like I can do that yet but just in case)

wwwarbird · « **Reply #25 on:** January 19, 2015, 05:54:56 PM »

Quote from: roger gebhart on January 19, 2015, 05:44:22 PM

How much fuel for fp to get through pattern. (not like I can do that yet but just in case)

That can vary but I'd put a 4 to 4-1/2 ounce tank in it.

roger gebhart · « **Reply #26 on:** January 19, 2015, 06:15:05 PM »

If I can run the tank over the top of the wing a little bit I can make that work. Gonna need some time to think this through

Mel Gray · « **Reply #27 on:** January 20, 2015, 12:34:50 PM »

Here is Bob Hunt's plan for the Pyron P-39. This is a superior plan to the original showing the as designed construction as well as an alternate nose construction for more modern engines and increased fuel tank area.

Mel

wwwarbird · « **Reply #28 on:** January 20, 2015, 05:45:05 PM »

Did Bob ever build one?

Balsa Butcher · « **Reply #29 on:** January 20, 2015, 10:09:14 PM »

I don't remember from the article if Bob built one or not. I doubt it or we would have read how how he won VSC??with it. I do know that Bob worked very closely with Walt regarding the re-do of the plans. Definitely designer approved. Consider an OS-35S rather than an FP. Close to a Fox in weight, plenty of power for a plane this size, same mounting hole pattern as the FP (although shorter case). A four once tank will be plenty with that engine, mine only use 3.5 ounces for the pattern.

Bob Hunt · « **Reply #30 on:** January 21, 2015, 06:31:05 AM »

Nope, I never built one; but I sure thought about it many times. I remember opening the American Modeler magazine in which it was featured when it arrived in the mail. I loved the great action takeoff shot that was included in the article. That always turned me on!

Walt and I became very close friends over the years, and we still communicate regularly. He's into running, dogs and fingerpicking on the guitar these days. He's hoping to get back into flying, but he doesn't have too much time with all his other interests...

I did work very closely with Walt to generate the updated plans, which corrected a few minor mistakes that were on the original plans, and we did add a sheet that showed the modified nose to accept a larger tank to accommodate today's more "thirsty" engines.

Dave Hemstrought did build one from the plans and he brought that model to VSC any years ago. It flew extremely well!

Later - Bob Hunt

Scott Richlen · « **Reply #31 on:** January 21, 2015, 07:08:54 AM »

Back in the 60s it was just such a joy to get American Modeler! It seemed like almost every issue there was another great-looking stunt ship like this one. Of course, I ordered the plans for it. Every once in a while on a cold winters night I'll get out my old box of yellowed plans and look at each one. They are still dreams. I loved all of the Parrot designs too. And when I got the issue with the Tucker Special! Oh my! What more could you want?

Make sure you keep posting pictures of your P-39!

Scott

roger gebhart · « **Reply #32 on:** January 21, 2015, 05:24:31 PM »

I was hoping you might chime in here Bob. I have both the 1959 plan and yours. I built the airplane to where it is from the early plan about 7 years ago and was unaware of the updated plan. What I have run into is the fp requires f1 to be moved back a bit so that even when f2 is moved back to the leading edge of the wing I start losing tank space. I could lengthen the nose just a bit but really would like to avoid that simply because of the extra weight of the fp. Still thinking. Got plenty to do while I figure it out. rog

roger gebhart · « **Reply #33 on:** January 21, 2015, 07:03:00 PM »

I'm trying to use something I have. If 4oz will do it I Have an fp 35. I can make that work with a little effort. I'm listening to all of you. So don't give up on me. Rog

Scott Richlen · « **Reply #34 on:** January 22, 2015, 07:39:49 AM »

Roger:

Don't use the FP-35. Unless they have been modified, they tend to "run away." You won't like what they do. As said before, the best thing to do is get an OS 35S. You'll love the way it runs, and it is more likely to fit. If not that, then the FP-40. Get one of your local guys to make a tank for you that will fit. Lately, I've been making deeper (thicker) tanks so they are shorter and fit short noses better. Plumb it per Paul Walker's recent remarks on uniflow tank making. We have had all kinds of problems with commercial tanks (rust, dirt, chunks of solder inside, pin-hole leaks, loose tubing) so we are making our own. In fact, late this winter our club will have a tank-making clinic.

Good luck!

Scott

Scott Richlen · « **Reply #35 on:** January 25, 2015, 06:02:06 AM »

Also:

Look at this: http://www.ebay.com/itm/AMERICAN-MODELER-July-1959-Bell-Airacobra-P-39-C-L-Stunt-/151547625640?pt=US_Radio_Control_Control_Line&hash=item2348f140a8

roger gebhart · « **Reply #36 on:** January 25, 2015, 08:50:59 AM »

I have a rally poor copy of tat article. So it's on its way. Larry Borden sent me a copy of Wales later article. Should b more than enough info now. Thanks. Rog

Author Topic: Walt Pyron p-39 (Read 4248 times)

John Leidle