Hobbico P-40 conversion questions. - RC Groups
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Apr 28, 2002, 03:29 PM
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Hobbico P-40 conversion questions.

Hello all,

After looking through the threads,I am gonna need your assistance for this conversion.I know the other thread addresses some of these issues but I thought I would ask here so I can get what I will need to complete it.

First off,do you need to remove any of the dehydral in the wing if you are gonna run aileorons?If so How do you go about doing it at the same time as strengthening the wing?

What gws gear box set should I get?How did you fit it in the fuse and did you add down/right thrust to compensate?

What is the maximum weight this will fly at?
I have the following components.

2*hs 50's
Gws 4pn receiver
Gws 2 amp speedo

Are these ok to use?

What batteries are you guys running?Anyone try lithium ions?

Any and all help would be appreciated.Please if you could post pics all would definately appreciate it.

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Apr 28, 2002, 07:53 PM
Strange Plane Central
frankenfoamy's Avatar
You have the right basics.
I converted the p51 that almost identical to your P40
Use the GWS motor direct drive by heating the pinion and melting it into the back of the stock spinner. (cut the spinner shaft off)
I use 6 cells from a rechargeable 9 volt battery or the ray o vac NiHD rechargeable 9 volt battery.
Reducing the dihedral is helpful when using ailerons.

More info is on my web page.

You will have fun
Apr 29, 2002, 10:19 AM
Registered User
I took all of the dihedral out of mine but mines AET, if you go RET you'll need about 5 degrees. The wings got to be stiffened, pull out the plastic spar and fill the hole with carbon fiber rod or bamboo, and you might want to skin the bottom (Frankenfoamies got some good stuff on doing this). Mines got a GWS 2S drive 6x5 and runs on 7-8 280nimh, but it should fly well on the GWS direct (I'm going to do their Spitfire with that) Horizons got a 3 1/8 x 2 Fly Zone prop that works great and epoxies on. If you keep the weight around 6 oz. any drive that'll give you a pitch speed over ~30 mph should work OK (I'm setting up their Zero S280/S300 direct).


PS I'm not familiar with the GWS 2A ESC, but that might be too small. GWS dd draws 2 - 2.5 A.
Last edited by Mikerjf; Apr 29, 2002 at 10:22 AM.
Apr 29, 2002, 10:27 AM
Strange Plane Central
frankenfoamy's Avatar
The 2 amp GWS ESC is rated at 2amps but I have used it up to 4 amps for extended periods with no problem. I have yet to burn one up so I do not know the real limit.
For some reason all the GWS ESCs are underated.

Example, You can use the 2amp version with the EDF50 which draws 3 amps on 6 cells
May 06, 2002, 07:21 AM
Registered User
I just finish the conversion of the spitfire this weekend. It's AUW is 4.0 oz but doesn't fly yet. I've set it up R, E, T. For power I am using the GWS 2amp speed control, GWS A motor direct drive (from a GWS cub) on 6 cell NMh 120 mah. I tried it with the gws 3x2 prop and bench tests showed ~13,000 rpm drawing 1 amp at full throttle. This however was not enough to get it airborn. On the first flight attempt it slowered down after launch, pulled left, stalled and went nose in. I have had to glue the front 2 inches of the nose back on and am ready for another try. I'm off to my LHS today for a different prop any suggestions?

Other specifics are GWS pico servos and GWS R4p reciever. I havn't stiffened the wing yet so still have the stock spar. Mounted the motor by creating a motor mount out of some thin plactic and glueing it to the nose. This kept the considerable down and right thrust that was original. I took out most of the dihedral by sanding it out of the bottom plate before CAing the wing halfs to it.

Anything else I should consider?
May 06, 2002, 10:07 AM
Registered User
This planes got a load of incidence in the wing saddle. To fly it's going to need down trim in the elevator, yours sounds like it had way to much up trim (climb, stall, wing over) it won't accelerate to flying speed in a steep climb. Mine's got the GWS S2 and fly's OK but it needs down trim. I've got the Spitfire that I'm going to try GWS direct, but it's not done yet. All the info on the Cox Viper conversion (frankenfoamy) will work on this.


PS Dump the spar
May 13, 2002, 03:20 AM
Registered User

Hobbico E-Fly Conversions

Converted a ME-109 last week, added a GWS IPS with a 3:1 ratio, 7-6 on 5x300 NImh cells, really flys well, and is fairly quick and responsive.
20" WS, about 5.5 oz AUW, about 5-6 minute duration and very tough on R-E-T using GWS Pico gear. Stock wing, some clear packing tape on wing bottom and tail surfaces.
5 different models to choose from (P-51, P-40 Warhawk, Zero, Spitfire, ME-109), about 2-3 hrs to convert, much less now that I know where it all needs to go.
Cheap fun for the park, strafe your friends quietly

IPS drive...love it, no RF noise, extensive repair job as the stock motor caused so much interference, that the third nose dive crash really did a job on it....and it still flys just fine. Use about 1/2 the right thrust and 1/2 the down thrust from stock, cut the fuse right above the exhaust stacks, as the area has to be hollowed out and the stock motor dug out. Then add a little more foam and a motor stick.
Fun to build.
May 13, 2002, 03:25 AM
Registered User

Hobbico E-Fly Conversions

Gear installation is tight...need to get the CG on the spar...
May 13, 2002, 03:26 AM
Registered User

Hobbico E-Fly Conversions

More details...
May 13, 2002, 03:27 AM
Registered User

Hobbico E-Fly Conversions

IPS 3:1 drive is shoe-horned in, works great!
May 13, 2002, 11:17 AM
Registered User
Steve McBride's Avatar
I need to check the micro forum more often!

The little P40 will do well with tailerons also. Just be sure to remove the dihedral from the wings. Otherwise you won't get a real good roll (marginal at best in my experience). Leave it in for rudder/elevator.

Like was mentioned above, the IPS motor direct (prefer the carbon brush model with heatsink) on the stock prop works great on 6 cells. Cut out the chin scoop and position the heatsink fins in the cooling sir stream! Make sure to have an exit though.

I used the stock on-off switch. Just remove the batteries and solder connectors to the circuit board. That way you can also use the stock charging jack if you want to leave the cells in place.

I'ts a nice little bird for sure!

Steve McBride
Mar 13, 2003, 07:51 PM
Registered User

Aim to fly indoors

For my P-40 conversion I'm considering:

>Motor: GWS/LPS-B2C-A. This motor plus gearbox weighs 12 g. The gb ratio is 4:1. With a GWS 5043 prop, thrust is listed as 50 g.

>Rx: Plantraco DSP 4-SC with built-in ESC (to 10 Amps)

> 2 Wes Tec 3 gram servos: aileron on one wing, and one half elevator.

> 2X145 mah Kokam LiPoly pack

How does this compute for those of you with experience here?

Ron Vanden Bossche
Mar 13, 2003, 11:44 PM
Registered User

Hobbico E-Fly Conversions

I gave up on these little birds - Tried the Me-109, P-40 and Spitfire (best due to larger wing), but all bit the dust so many times. Other E-flyers had the same or worse situations.

They are very challenging and fun to try but...

The wings are too flexible to maintain torsional rigidity when all the new gear and batteries are added (weight is doubled from stock). Any manuveer that requires pulling some G's got the little wings bending and flexing so much that the controls just could not overcome the rapid changes in flight, ending with uncontrolled crashes. The controls could be seen moving but had little effect.

Have been flying a 24" foam Rare Bear AUW 8 oz with the same overall dimensions but the wing is 1/4" foam undercambered (like the E-Fly ships) with ailerons and torque rods. Wing is much stiffer with more wing area and it flys great!

To do that much work to the E-flyers, might as well pay for the engineering and have a lot more fun.

Now the P-51 foamie that has the semi symetrical wing should work well, and is on the shelf awaiting completion. All the practice with the E-flyers will come in handy.

Good luck.

Mar 14, 2003, 02:39 AM
Electric Coolhunter
Thomas B's Avatar
My new Zero conversion is doing well and is not too terribly heavy with a small Li-poly pack and the GWS direct drive. The Zero with the somewhat larger fuse has enough room for a 2 cell 1020 Kokam pack. It flies until I get tired of it.

I don't think the milder motor from a stock GWS A drive will do as well on direct drive with the 3-2 prop. The true GWS driect drive motor is much hotter than the stock A drive motor. My Zero goes like gangbusters on the DD GWS.

Sam2000pres is right, though. The wings are just not really stressed for what we are doing. I added some carbon tow to the bottom of my wing and it still bends badly. I am thinking about adding a kevlar thread for one wingtip to the other and running it across the bottom of the fuse to create a bracing wire that is almost invisible.

I have a P-40 to convert next. that fuse will take some whittling to make room for my 760 mah Ultralife Li-poly pack.
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Mar 14, 2003, 12:25 PM
Registered User
Thanks for the quick replies, guys.

sam2000pres: what is the P-51foamie you mentioned?

Ron Vanden Bossche

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