P40 Build
- Thread starter moke
- Start date
PaulBlack71
New member
Given your info, I would guess it's the foam board then. Seems to be the only explanation. Mine's 31 oz with full fpv gear on board but using flite test actual kit (adams readyboard) the plane itself without electronics feels nearly weightless.
I have a bunch of adams readyboard here. Will weigh a untouched sheet and post if it will help.
1 sheet 20in x 30in is 4oz or 115 grams.
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Dunfielder
Active member
I found a thread talking about the material you used I believe.
https://forum.flitetest.com/index.p...utside-the-usa-us-citizens-pls-read-too.3558/
Looks like that stuff is over 300 gr a sheet if its 70cm x100cm. So you are correct in assuming that the material is heavier. That being the case I'd still get rid of all little extras that add weight. Just build a plane that is plain and simple then get a weight. Your gonna be heavier even then. I would also get a motor that produces more thrust. If you got enough thrust even a brick will fly ie: the space shuttle. I believe the guy who talks about using this material is in Spain and he said it messes with the CG.
https://forum.flitetest.com/index.p...utside-the-usa-us-citizens-pls-read-too.3558/
Looks like that stuff is over 300 gr a sheet if its 70cm x100cm. So you are correct in assuming that the material is heavier. That being the case I'd still get rid of all little extras that add weight. Just build a plane that is plain and simple then get a weight. Your gonna be heavier even then. I would also get a motor that produces more thrust. If you got enough thrust even a brick will fly ie: the space shuttle. I believe the guy who talks about using this material is in Spain and he said it messes with the CG.
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daniZZ
Active member
Right, it is a pita to get the CG where it should be without the spinner which is quite heavy and it is right on the nose of the plane.... Even with the spinner it is not easy to get it there....the battery has to be flush with the front-end of the fuselage....
So is there any chance to get it airborne????
Dunfielder
Active member
Sounds tail heavy to me from your description of the first planes maiden. Especially if the battery has to go as far forward as possible. If I did that with mine it'd be a lawn dart. Also the fact you need a heavy spinner to balance tells me tail heavy. You have two options danizz as far as I can tell. Hang this beautiful plane on the wall for an awesome conversation piece and start again but building with no frills. Or option 2 which I think is not the way to go. Add more nose weight inside the hatch up front and try a flight. Preferably somewhere with tall grass in case things go sideways. Trial and error buddy, trial and error.
Dunfielder
Active member
That's a good idea to lose some tail weight. I hardly touch the rudder personally. Bank and yank baby!!!!
Dunfielder
Active member
I also think your motor should be fine after reading about your first plane. It flew, vertically but it flew. Might be harder on your motor as it will work harder, and probably drain batteries faster, to lift more weight but it got you up. Seems more of a CG problem than anything. I still think you should lose the gear. My P40 has been crashed 5 times and survived with no gear. Marty72 told me planes survive crashes much better sans gear and he was right. Just toss and belly land. Sounds like you ended up tossing it to launch anyway. I'm rooting for you! Try and get someone to video your flight so the experienced guys can offer the best possible help. That's what I do.
daniZZ
Active member
5mm thick, can't weigh a sheet, I was using 70x100 mm sheets and don't have one right now, I have only scrap right now....
Dunfielder
Active member
As I said earlier that material according to another thread is over 300gr a sheet. Almost 3 times the weight of readi board. To save enough weight you'd need way thinner foam, and then you end up having to modify plans, and in the end you'd have a pretty spindly plane that wont take any abuse. By the way there is a thread on here of a guy who makes his own foam board with amazing results. Maybe that would be an option for you danizz?
Dunfielder
Active member
Sounds like you really want to try it. Go fly it man! I know the feeling. What's the worst that could happen? You wreck it? That's part of the hobby my friend. I don't know how much the foam costs in Romania but it can't be that much. Go ahead and fly it! That's the beauty of FB planes. Cheap to build. Add some nose weight first if it balances tail heavy to get it slightly nose down. I know you think weight is your problem but I believe CG has much more to do with it as you did get airbourne before.
BATTLEAXE
Legendary member
Fly it man. Whats the worst that happens. It finds the dirt and you start fresh. Build a lighter one if possible
Cobra1365
Active member
Give it a test hop. But, keep the turns flat and don’t climb out steep. An overweight airplane is going to be more difficult to control. But, you’ll find out on the first circuit if it’s too heavy. If it’s obviously slow or mushy on the controls, that’s likely the culprit. After all, even a brick will fly if you add enough power! 
Dunfielder
Active member
BATTLEAXE
Legendary member
I used the 3536 1200kv on 3s and it flew alright, not 4s fast but flew well. Are you using 4s on the 940kv?
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