Heli-NuBee

My GP PT-17 Stearman build has been pretty standard until this point. Now the build will get a bit more interesting from this point forward. I am in the process of adapting the engine mount for the radial engine. GP PT-17 Stearman, ASP 400 AR five cylinder radial engine, Keleo exhaust, Microsens on board glow system, Microsens glow system balancer, Master Airscrew 20x8 prop.

Best wishes and good safe flying.

Heli-NuBee (AKA Roger the radial rabbit)

Heli-NuBee

OK, the GP PT-17 Military Stearman is complete and ready for its maiden flight. For some reason, I can't seem to get pictures uploaded on this forum. See the following forum for pictures http://www.rcuniverse.com/forum/m_6767296/tm.htm

Heli-NuBee (AKA Roger the redial rabbit)

jp928

My Feedback: (5)

FWIW, I have just finished mine. With a Moki 135 mounted ~ 1/4 further fwd than stock, and main servos mounted forward just behind the tank area, a 2300mah A123 battery, it balances...on the button. I made my own prop nut out of 3/4" hex mild steel bar to help a bit. No unecessary lead needed, or even the box for it!
beautiful

Next comes a test flight...eventually.
I think i finished up with low wing at 1.5Deg+, top wing at 1.0 deg +, with respect to the stab.
jp

Heli-NuBee

I made just a few modifications to my plane. The original engine mounting bolts were #8 and I changed to 1/4" for the adaper plate where the engine mounts using five #10 machine screws. The engine adapter plate is made from two pieces of 1/2" high quality plywood. I felt the larger bolts should be used for the more powerful radial engine. It took a full pound of lead in the tail to balance with the ASP 400 five cylinder radial engine. GP P-17 Stearman, ASP 400 five cylinder radial engine, Microsens on board glow and glow balancer systems, 32 oz tank, Futaba 2.4 seven channel RX, high torque metal gear servos and Master Airscrew 20 x 8 prop.

Best wishes and good safe flying.

Heli-NuBee (AKA Roger the radial rabbit)

Heli-NuBee

I had a great time today with the ASP 400 five cylinder radial engine powered GP PT-17 Military version Stearman. The maiden flights went very well and I finally got good flights and landings with this combination. I am like a kid with a new toy! The plane is not over powered but flies very well. It feels quite heavy (I have not weighed it) but still lands well. This is a great combination and I am now a happy camper. I am now looking forward to our annual War Bird event this comming Saturday to show off this plane.

Best wishes and good safe flying.

Heli-NuBee (AKA Roger the radial rabbit)

Heli-NuBee

Go figure, My ASP 400 five cylinder radial engine in the GP PT-17 Military version Stearman outshined both my Saito 200 three cylinder radial and my UMS Evolution seven cylinder radial engine today at our annual War Bird meet. The three cylinder Saito in the Sea Fury. kept loosing a cylinder and the UMS seven cylinder lost power in a low camera pass causing me to put it down in a plowed field doing considerable damage to my BH Corsair. The ASP 400 ran strong all day. The ASP is the least expensive of the bunch but was best today. On the bright side, there was a fellow shoot some good video and I think he will share it with me in the near future.

Best wishes and good safe flying.

Heli-NuBee (AKA Roger the radial rabbit)

j301

My Feedback: (12)

By all means, share! Sorry to hear about he F4U, that's always a bummer, especially whens its a cool bird like that. Did you have the breakage issues with the ASP crank, and if so was it a PITA to fix?

Heli-NuBee

Hey J301, no I have not had any issues with the ASP 400 as yet but I only have about six ten minute flights on it so far. I has run very well so far.

Best wishes and good safe flying.

Heli-NuBee (AKA Roger the radial rabbit)

j301

My Feedback: (12)

I've sworn myself off glow to switch over to all gas, then I look at engines like your radial and there's that little voice in the back of my head "just one more,,,"!
Glad to hear yours wasn't one of the afflicted ones. Looking forward to your videos.
As for mine, tried to take it out this weekend for a long overdue sortie, but the ignition battery was toast. I was using an old 3000 mah 4c nicad for ballast and had it buried way in the nose, so off it all came today (tank, cowl, various guts) and had to put a 3 cell NiMh on order. It will be a cell short of the last 4c pack, so I will have to build a box over the motor to try and get the weight fwd. Im using a G26 so the ignition is battery hungry (and runs better at 3c or single cell lipo or LiFe=the best choice), but I need the lbs anyway. I have been switching everything over to A123/LiFe so it kind of sucks having to go old school one last time, but it is what it is!

Zampa

Hi everybody! Some days ago had the maiden flight of my Great planes Stearman with the evolution radial 7-35. The engine ran beautifully and the plane flies very scale, perfect combination (as you may have seen along this thread )
You can see a nice video of the maiden here http://youtu.be/X8JvLRyOgK8 edited by my good friend Andrea.
Hope you like it

Heli-NuBee

Hey Zampa - Nice video - thanks for sharing.

Heli-NuBee (AKA Roger the radial rabbit)

maxiemac

Seems I'm a late starter in this thread since it started in April 2005 but I'm not a late starter with a PT17 as in the early 1980's I built the Stirling 64-1/2" wingspan kit of this model and still have it - like many others on this and the other super stearman thread, I too found lots to like about the model but equally lots not to like including all the comments I've read on both threads about wrinkles, undercart, wheels, balance point and wing incidences etc etc not to mention the amount of missing detail including no hand grips on the wings or fuz and the wrong position of the horizontal stab trailing edge that should be forward of the rudder post - but then again this was built to a price and not a formula - want a better model? build it or buy a better one and pay more.

I'll try and post a few photos of mine just to show how I approach assembling these arf things - items such as how to measure from the prop driver back to the firewall, how I fixed the cowl to the fuz front, hide the battery up the front, move the servos forward, setting up and attaching the wings long before attaching the tailplane and a myriad of other details just to hopefully end up with 'a model put together as best I know how'.

keep smiling and cheers - maxiemac from 'downunder'

stevelesl

Chris Peterson, I am about to mount my Saito 325 on the GP PT17 but the mounting holes are right in line with the two ply side formers that protrude through the bulkhead, how did you mount your engine ?

ChrisPetersen

My Feedback: (3)

I built a adaptor out of ply wood. The motor as I remember needs to be spaced out almost an inch so I cut one piece of 1/2 plywood the size big enough to fit between those formers and drilled if for the bolt pattern on the plane, then another 1/2 in ply that fit the radials bolt pattern. I then had to lighten it up and bolt it together. The only big hassle is the initial assembly because you have todo it with the cowl on but once it's fitted it works brilliant.

stevelesl

Thanks, I was kind of leaning that way too but was concerned as I didnt want to have the engine any further forward than it needed to be because of the CG issue, I will do something along the lines of what you did. Are you still flying it ?

ChrisPetersen

My Feedback: (3)

I just made sure to position my batteries in the tail and it came out fine. I agree there's a trade off with putting it out too far but it handles the weight great! Be careful with the spins though because the mass wants to keep spinning. I buzzed a rabbitt hole trying to recover from three mistakes high! Yep she's still flying. It's my kick back and putt plane at the end of the flying day.

45AIRPLANE

I have crashed my super stearman ( GP ) and have rebuilt it. Does anyone know the incidences of the wings and hortz. stab and eng.

stevelesl

You will see that data on GP site under technical data, top and bottom wing and stab 0 deg, 3 deg right thrust and 1 deg down thrust

stevelesl

Here is my Saito 325 mounted, looks pretty good, cowl cut down fits to cover the engine mount too, more pics later

bigbird3

Hey buddy, looks really great! I think a 170 would be about as large as I would go on the GP Stearman. A 325 is right at twice that! I'm thinking it will over power the plane and stress the cabains as they are only anchored with wood screws. Do you know of anyone putting this engine or one equivalent on the Strearman? I think that engine would be better suited on an 80" Stearman! At any rate, I wish you great success with the combination. How are you on balance? Are you putting any weight in the tail? BTW, I use to drive trucks in Pearland back in 1978 for French before they became French! Ran a tire truck there too for a while. I lived in Baytown then. Now I'm in the north enjoying cool summers and Cold snowy winters! Big change! Not much humidity either! It cools off to high 40's to low 60's at night in the summers! UMMMM! great sleeping weather! hehe!
bird.

stevelesl

See post 579 above, Heli-Nubee has ASP 400 on the PT-17 with great success, looks like about 1 lb required in the tail so I have built a hatch to place my 5000 mah 1.2v sub c onboard glow system battery pack which weighs about 9 Oz, may have to put more weight too but the planes large wing area will still allow a wing loading of @30 Oz per sq ft. Others have used this engine too, should be about 18 lbs all up and remember, you can always throttle back .
I have seen several OS and Saito five cylinder engines on planes this size (GP Waco is one) that fly and sound great. Weight of the whole plane in a loop with any engine has more of an effect than just the actual structure weight, in any case, I'm using this engine more for the sound and looks than actual performance although performance will be pretty cool .
if you use a 120 size 4 stroke on the plane and add say 15 Oz in the engine weight box you are getting up to about 45 to 50 Oz in the nose, the FA-325 weighs 84 Oz so actual added weight is about 2.5 lbs, not a lot for a plane with @1500 sq inches of wing that should be say 14.5 lbs to 15 lbs giving a very low wing loading as standard. We will see, I will post more pictures as I progress.

bigbird3

Very nice Steve. I didn't realize it was commonly used on this plane. Mine is around seventeen pounds with a G-23 so you are definately in the ball park. Yes, as long as you don't intend to fly it like a 3-D it will be a stunning flier. Thanks for the reply and please keep us all posted.
Very best wishes.
bird.

stevelesl

I am bout to do the cabane install and wondered if anyone has thought about or done this, instead of the wood srews to hold the fuselage cabanes, install bolts with nuts inside fuselage, thoughts?. I have not checked to see if I can get the nuts on the back of bolts if I do go this way, just checking to see if anyone has done it.
More pics to follow in a few days as I am getting close to having the whole thing together with the Saito FA-325.

handyman 220

My Feedback: (54)

Yes, it can be done. I have made this mod on all my GP bipes, Pitts, Stearman and P-6E Hawk

stevelesl

thanks