Micro All-Balsa P-40 Home Build - RC Groups
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Jun 24, 2012, 09:28 AM
Wait till ya see MY flying
Stuntman Smithy's Avatar
Build Log

Micro All-Balsa P-40 Home Build

Hi guys! (and girls!)

For a long time now I've been in love with micros, especially warbirds, and while I really have very little experience compared to most, I love designing and building my own planes. After getting my first micro (the PZ corsair) and falling in love with the scale realism I decided to design and build my own -except hopefully stronger and lighter.

Sounds mad with what little experience I have I know , but I'm perfecting my plans as I'm going and it seems to be going pretty smoothly.

Here's where I'm up to so far:

P.S. Just so you know, I don't have a home internet connection and this is pretty much my first thread, so be patient with me, it could take some time lol
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Jun 24, 2012, 10:13 AM
Wait till ya see MY flying
Stuntman Smithy's Avatar
So, I started out with a free plan of a petrol (!) P-40 I found of the internet and I basically shrunk it down on my computer then traced it onto a sheet of paper leaving out any unnecessary bulkheads, formers etc.

After that the biggest problem was working out a way to get to the radio gear as I still have it in my micro corsair for now. I ended up basically copying the hatch design on the corsair, hopefully there won't be any unforeseen problems with it.

I kept the main keel design but changed it to a full profile rather than stringers with the hope of hollowing out as much as possible after planking one side. I then put in a flat plate in for the motor and brick to sit on and that's about all. All the planking is in 1mm balsa with everything else in 1.5mm except the nose, which is in 2x 3mm for thickness and strength.

As for the wing I'm thinking about using a 1.5mm sheet over 3 formers and a spar. I'm not 100% sure on this so any opinions would be great.

Btw sorry if the photos are crappy quality, they're the only ones I've got
Jun 24, 2012, 10:20 AM
Wait till ya see MY flying
Stuntman Smithy's Avatar
Unfortunately these are the earliest build photos I've got, as I didn't actually intend to do a build thread on it.
Hopefully they're early enough to get an idea of how I started and there's still the other side to do in any case.
Jun 24, 2012, 10:41 AM
Wait till ya see MY flying
Stuntman Smithy's Avatar
Here's one example of changing the plans as I go . The bottom of the keel is quite curved and unfortunately I didn't take it into account as I planked down. So I ended up with the side almost straight that needed to become a pretty hard curve in one plank .

So instead I ended up cutting that part of the keel and former off and replacing it with 2 sheets of 3mm that I'll just sand to shape. It'll surely add some unnecessary weight but it's also the part that'll hit the ground first on landing and strength is more important to me than weight at the moment.
Jun 24, 2012, 10:51 AM
Wait till ya see MY flying
Stuntman Smithy's Avatar
With one side entirely planked I started attaching everything I couldn't while working with one side flat to keep it straight.

The tail end of the keel was cut out to save weight but with so little space between the formers at the front I couldn't see the point of trying to cut out any more. When the hatch is cut off (which at the moment I'm waiting to do after it's fully planked on both sides) I'll take a dremel to the inside of it to hollow out the keel and formers as much as I dare to.

With all the unnecessary 3mm plating on the nose end and lack of lightening I was worried about the weight, but at 10 grams it looks pretty positive!

Btw the huge cut out in the front is for the motor and gearbox.
Last edited by Stuntman Smithy; Jun 24, 2012 at 11:01 AM.
Jun 24, 2012, 11:29 AM
gklein's Avatar
I love the construction technique and you are doing a superb job! Good subject too - narrow fuselage!
Jun 24, 2012, 11:38 AM
Wait till ya see MY flying
Stuntman Smithy's Avatar
And this is where I am at the time of starting this thread!

Any and all opinions are welcome! At the moment the control rod placements, battery access, entire wing design and placement of the wing servos is kind of at a best guess stage, so any help on those would be awesome .

Also any lightweight finishes that have been tried and tested would be helpful as I have no idea how I'm going to finish it.

My scales might not be very precise but I'm getting 11g at this stage and with all the balsa I estimate I'll need to finish the fuselage 12-13g! The entire bare balsa aircraft minus radio should be under 20g?!?! I'm not sure if that's heavy or light in home builds but I'm well pleased! (The radio gear should weigh around 18g for a AUW of approx. 35g-40g ie. the same as the corsair)

I'll do my best to update this as often as possible and answer any questions but it might be a bit hit and miss.
Last edited by Stuntman Smithy; Jun 24, 2012 at 02:33 PM. Reason: Added radio gear weights
Jun 24, 2012, 11:39 AM
Wait till ya see MY flying
Stuntman Smithy's Avatar
Thanks Gklein!
Jun 24, 2012, 12:36 PM
No more nicotine for me!
micro_builder's Avatar
I'm with Gklein, the construction method is good, I've used it a few times myself. 11g isnt too bad for all the wood thats there either...if all else fails you can drill some holes here and there (well, on the next one at least, its harder to do when you've already got it planked ). Looks like it'll be a good looking model, nice work.

Jun 24, 2012, 02:19 PM
Wait till ya see MY flying
Stuntman Smithy's Avatar
Really? Awesome, have you used this method on micros or just "standard" aircraft? So you actually think 11g is quite heavy for a micro fuz? If so I might be able to shave off some more weight here and there.

I kinda wanted it beefy from the start. I just hate how fragile the foam micros are. But I really have no idea what's beefy and what's just overkill on this sized model! So if the consensus is it doesn't need, it I'll shave it. Thanks man
Jun 24, 2012, 03:08 PM
Registered User
Looking real good....

Jun 24, 2012, 03:54 PM
Pilot, Co-pilot, Navagator
nemoskull's Avatar
looks great! the planking method you use will be heavier than the stick and tissue method, tho the p-40 was a heavy fast plane anyways, so i find it appropraite.
you might want to look into a BL system. the airframe is over strong for the stock geared 8.5mm brushed setup from any UM p51.
ive been wanting to do a p40 for a while now! i love your thread.
Jun 25, 2012, 11:04 PM
No more nicotine for me!
micro_builder's Avatar
I've used that method on one 32" foamy I built, and a few micros. They tend to weigh a bit more than stick and former type construction, but they're also usually quite strong. 11 grams isnt too heavy, I think a lot of my airframes come out around that weight actually, and for the amount of balsa there, its not bad.

Best way to determine if you've over built is have a few crashes, if it holds up perfectly, then you know its plenty sturdy. Then if you build another, you know you can do away with some wood and go lighter...a lighter plane will almost always perform better.

From the looks of things so far, should turn out to be a very nice looking plane


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