An absolute beginner scratch builds an FT P-40. Now with maiden vids
- Thread starter Dunfielder
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Dunfielder
Active member
Didn't notice Marty72 had built one until now. I'm just going off the build video and what I've read here. Hell they put it up in big letters across the screen during that part of the build. In a post titled "*unofficial* FT P-40" people are asking about the CG because the plans differ from the build video. One poster said he contacted FT and was told 1/2 an inch is correct. Others in that thread posted they were really nose heavy at 1.5 to 2 inches CG. It contradicts what the plans say, there is obviously a mistake somewhere! If its 2" than I'll be fine but if its half an inch I'm tail heavy. Again I'm not trying to argue with anyone just looking for an answer due to the confusion.
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BATTLEAXE
Legendary member
Rule of thumb for the CG will be 25-33% of the wing chord. Things get a little more complicated with swept back wings but the P-40 has a straight leading edge so it is easy. Measure the full wing chord, multiply by 0.25, and that would be the measurement for CG placement as far forward as you want. Do the same calculation at 0.33 and mark that measurement as well. CG marks is not an exact science, they are more of a reference. If your CG is outside these 25-33% parameters there is a good chance the plane will crash. If you are inside these parameters then it will be enough to fly the plane and get it trimmed out to balance or even recover to land without incident. From there after the maiden you can fine tune from there.
I will say that a half inch from the LE is to nose heavy and it will find dirt quickly. I understand that you want this to fly perfect but the thing is that everyone builds different. You and i could sit side by side and build the P-40 each, chances are both planes will have a different CG to some degree. Then it comes down to what the pilot preference is. I like to fly my planes nose heavy, just because i like the speed and penetration in wind. You being a beginner might like your CG further back for the lighter loftier feel of a trainer plane. I wouldn't get all stressed out trying to interpret the discrepancies. Get the CG close to the 1/4-1/3 marks and fly it, its the only way to tell.
This might have been referenced before but how much piloting experience do you have? If this is your first time then there are so many other variables to consider. You could build the perfect plane with the perfect CG that has been proven as a perfect flyer and you could toss it up and dive it into the dirt just because of lack of experience. If this is your first and you have put a lot of effort into it, I understand how the anticipation of a good first flight is exciting mixed with the possibility of totally deep sixing this thing into terra firma on the first toss. You want to make sure the plane is right to eliminate the possibility of the plane being at fault, when really you need to dial in the skills.
If i was you i would try the P-40, and if the maiden goes well, it is a unicorn story. Congrats. But do understand that if this will be the first time you fly you will crash it, and fix it only to crash it again. This is a rinse and repeat operation. In the beginning for me i went through a dozen planes before i even got 30 seconds of continuous flight time, and the plane that did it for me was the Mini Scout, one of the simplest planes to build, I could slap one together in an hour now. I have built 6 different Scouts since then and still enjoy flying them. You might go through a dozen P-40's to get the same results, its not uncommon. Just get out and fly man, that will be your test bed, then worry about the planes. Good Luck
I will say that a half inch from the LE is to nose heavy and it will find dirt quickly. I understand that you want this to fly perfect but the thing is that everyone builds different. You and i could sit side by side and build the P-40 each, chances are both planes will have a different CG to some degree. Then it comes down to what the pilot preference is. I like to fly my planes nose heavy, just because i like the speed and penetration in wind. You being a beginner might like your CG further back for the lighter loftier feel of a trainer plane. I wouldn't get all stressed out trying to interpret the discrepancies. Get the CG close to the 1/4-1/3 marks and fly it, its the only way to tell.
This might have been referenced before but how much piloting experience do you have? If this is your first time then there are so many other variables to consider. You could build the perfect plane with the perfect CG that has been proven as a perfect flyer and you could toss it up and dive it into the dirt just because of lack of experience. If this is your first and you have put a lot of effort into it, I understand how the anticipation of a good first flight is exciting mixed with the possibility of totally deep sixing this thing into terra firma on the first toss. You want to make sure the plane is right to eliminate the possibility of the plane being at fault, when really you need to dial in the skills.
If i was you i would try the P-40, and if the maiden goes well, it is a unicorn story. Congrats. But do understand that if this will be the first time you fly you will crash it, and fix it only to crash it again. This is a rinse and repeat operation. In the beginning for me i went through a dozen planes before i even got 30 seconds of continuous flight time, and the plane that did it for me was the Mini Scout, one of the simplest planes to build, I could slap one together in an hour now. I have built 6 different Scouts since then and still enjoy flying them. You might go through a dozen P-40's to get the same results, its not uncommon. Just get out and fly man, that will be your test bed, then worry about the planes. Good Luck
Dunfielder
Active member
As the thread title implies I have very little stick time. I expect to crash. I just want to give myself the best chances for any kind of flight however short it may be. Just trying to not build a lawn dart or a rocket to the moon. I will definitely Take your advice BATTLEAXE. As soon as we get a nice day I'm going to maiden it and probably beat it up lol. I will put up a vid for everyone to have a chuckle because it's bound to be funny!
BATTLEAXE
Legendary member
The cool part about the vid ids the rest of us will not only be entertained but it helps us diagnose any issues you might have to give you the best chance to fix it, whether it is the plane or the piloting. That is a great idea. Have you got a sim to play with until the weather cooperates? Those help improve the stick skills on the off times, helps develop muscle memory for the real thing.
Marty72
Elite member
I've built 2 P-40s, have over 100 flights on them.......and yes it is a big deal (at least to me, not so much for others). Anyone who has read any of my post knows I'm obsessed getting the cg right.
A plane with a perfectly located cg flies amazing, a little forward or back and it flies but just not as well IMO. The CG location I've settled on with the 1st P 40 was 1.75 inches (2.0 spec), the cg on the 2nd P 40 works best at 1.50 inches. I would suggest for a beginner using a slow fly prop, spec motor, in the range of 1.5 to 2.0 inches fwd of the LE for the first flight. I don't know why .5 inches is suggested in the video, but I believe that's bad data. The plans and the FT website both say 2.0, and that's in writing. That's what I used as a guide. BTW, I've settle on a cg slightly ahead of the spec cg for all the FT Warbirds I've built (P40, P51, Spitfire). Will a .5 cg off the leading edge fly, I don't know, but I'd be surprised if it flew well. After the first flight, you can adjust cg as needed. If you take video, you'll be better able to access what really happened (if things don't go well). You can learn a ton from a video as a beginner (because you senses will be over loaded).
Battleaxe is right on, 100% correct as usual, on his above statements. Yes, a beginner is a little better off with the cg a tad back, faster fliers like cg a tad forward. As speed increase, cg needs to move forward a bit. I run a larger motor and prop than spec (1200 35-36 rimfire w/ 10x7 prop). I've also have many flights with the "c pack" motor (9x6 prop) and it works fine, it just doesn't have the vertical capability of the Rimfire.
2nd P 40
BTW, for balancing, I use nickels, 5 grams a piece. I glue inside the foam walls if needed.
Dunfielder
Active member
No I don't unfortunately. But I did try one on my cell phone. I could take off, circle and land the trainer Absolute RC or something is the name of it. The controls are absolute trash though lol. Crappy touch thingys. I kinda want to wrap my index over the top of the stick with my thumb on top of the stick. I flew with thumbs when I was at the local club and buddy boxed a couple times and It isn't as natural feeling for me. I found it too touchy almost for my chubby thumbs to be precise I have way too many hours on actual flight sims like IL2 BOS. This in turn makes me want to hold the little gimbals more like a tiny joystick. Sounds funny but its true. It also makes it difficult to get used to using such small movements due to the very short sticks compared to the Thrustmaster joystick lol. The rudder is a bit iffy as well because it wont be on my feet, and the throttle slides up and down super easy so I'll probably end up all over the place lol. Like I said it'll be entertaining for 2 seconds if nothing else!!!
Dunfielder
Active member
I've built 2 P-40s, have over 100 flights on them.......and yes it is a big deal (at least to me, not so much for others). Anyone who has read any of my post knows I'm obsessed getting the cg right.
After the first flight, you can adjust cg as needed. If you take video, you'll be better able to access what really happened (if things don't go well). You can learn a ton from a video as a beginner (because you senses will be over loaded).
Battleaxe is right on, 100% correct as usual, on his above statements. Yes, a beginner is a little better off with the cg a tad back, faster fliers like cg a tad forward. As speed increase, cg needs to move forward a bit. I run a larger motor and prop than spec (1200 35-36 rimfire w/ 10x7 prop). I've also have many flights with the "c pack" motor (9x6 prop) and it works fine, it just doesn't have the vertical capability of the Rimfire.
2nd P 40
View attachment 173465
BTW, for balancing, I use nickels, 5 grams a piece. I glue inside the foam walls if needed.
Thanks man!! This is good news as my plane wants to be slightly nose down at like 2" to1.75" from the LE. Come on sunshine!! Daddy got a plane to crash.
BATTLEAXE
Legendary member
Thats the spirit. More crashing develops the building skills. Its a win/win to crashing
Dunfielder
Active member
Looks like summer is cancelled up here. Nothing but rain for a week now and nothing but rain in the forecast. This morning it stopped long enough to get out for a maiden. wind was blowing 10 to 15 km/h outta the west. So for your viewing enjoyment....
The very first launch
Typical I guess lol. The battery ejected but no damage. Then on the next try
Holy crap Batman that got hairy!! Had a good laugh. The wife missed the loop I pulled when I went back towards the road which sucked because it was awesome, you can hear me and my brother cheering. soft landing in the tall grass. No damage so far. Then attempt 3
Wow that was a wild ride right into the ground. I am not complaining one single bit though, I think I did ok for a first timer. Had so much fun with my brother, wife , and the kids there to get a giggle. That last smack was pretty decent so here's the damages
I'm sure Cooter can fix that up. So there you go everyone. The absolute noob builds and flies, (kinda), a FT P40. Hope you enjoyed it. Please give me your thoughts on it. You'll see the general again I'm sure!!!
The very first launch
Typical I guess lol. The battery ejected but no damage. Then on the next try
Holy crap Batman that got hairy!! Had a good laugh. The wife missed the loop I pulled when I went back towards the road which sucked because it was awesome, you can hear me and my brother cheering. soft landing in the tall grass. No damage so far. Then attempt 3
Wow that was a wild ride right into the ground. I am not complaining one single bit though, I think I did ok for a first timer. Had so much fun with my brother, wife , and the kids there to get a giggle. That last smack was pretty decent so here's the damages
I'm sure Cooter can fix that up. So there you go everyone. The absolute noob builds and flies, (kinda), a FT P40. Hope you enjoyed it. Please give me your thoughts on it. You'll see the general again I'm sure!!!
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Dunfielder
Active member
Thanks @danskis! I just tried to not power it into the ground as best I could. I honestly felt real good about my first real flight. They were both far longer than I expected! I already have the general just about fixed. Hopefully it still flies nice. I never touched the trim buttons on my flights, too preoccupied trying to stay up!
Dunfielder
Active member
Cooter got her all patched up. Not pretty but who cares. I’m pretty sure it’ll still fly
Marty72
Elite member
Wow! that went really good for a first time. I'm glad you decided to go without landing gear, planes survive crashes way better without gear.
You also did something else good, having someone else launch the plane. On my first attempts, I did the hand launch and was trying to get my hands back to the sticks. It gets you behind the curve, and sets you up for failure.
You did a great job getting off the throttle when you were about to crash. You saved the plane by doing that.
After watching the videos, the plane looks like it flies well slow, which is great for learning. My advise is to get that plane up high and just try and stay up. It's tough to trim when you are new at this, I crashed a few times trying in the beginning.
Remember, the longer you stay up, the more you learn. So next time, get the plane up high, way up...this will give you more options.
You also did something else good, having someone else launch the plane. On my first attempts, I did the hand launch and was trying to get my hands back to the sticks. It gets you behind the curve, and sets you up for failure.
You did a great job getting off the throttle when you were about to crash. You saved the plane by doing that.
After watching the videos, the plane looks like it flies well slow, which is great for learning. My advise is to get that plane up high and just try and stay up. It's tough to trim when you are new at this, I crashed a few times trying in the beginning.
Remember, the longer you stay up, the more you learn. So next time, get the plane up high, way up...this will give you more options.
Dunfielder
Active member
Thanks @Marty72. High praise coming from someone with far more experience! Yeah I wasn't about to try and launch myself, I knew it would go bad lol. Only reason I went with no gear is where I fly is tall grass that would rip it off I figure. Now that I have some advise on the gear I'll leave it off. The wind pushed me around a bit but I found my ailerons super touchy even with 50% expo! Next time I'll try to stay higher for sure. Thanks again man!
Marty72
Elite member
I watched the videos again. You need about half throttle to fly this plane (of course, I can't be sure how you tx is set). The last video, you didn't have enough speed and you were fighting a stall (you probably already know this).
Check all the control surfaces and make sure the power pod is in there secure before launching again. The plane is in amazing shape for 3 crashes. You are on your way, just get altitude next time!
Check all the control surfaces and make sure the power pod is in there secure before launching again. The plane is in amazing shape for 3 crashes. You are on your way, just get altitude next time!
Marty72
Elite member
I may have more experience but I started flying in October of 2019, so still remember what it is like to be a rank beginner.
The ailerons were a problem for me as well, my first 7 flights, I got a total of about 7 minutes of flight time. The 8 flight and I stayed up for full time. It was awesome.
Ailerons: expo is great but you can reduce the throw on them in the TX and you should. You don't need all that authority now. I'd take it down to at least 70%, you could probably go as low as 50% and be fine. The thing that made me crash, was overly sensitive ailerons. If you can set up low, med and hi rates on your TX, I would. If that's the case, use 50% for low, 70 % med and 100% for high. 50 % expo if fine right now.
I'm going to repeat myself again, Elevation, elevation and elevation. I did the same thing as you and I had people telling this, it's not easy, but it's what you need to hear.
Dunfielder
Active member
You are absolutely right sir. All my level flight was 50% throttle on my Flysky I6X. I ended up at less then that quite a bit trying to save it! Battery was still at 87% after the last crash. The final crash I was climbing into the wind and didn't have enough speed, dropped a wing to turn and it stalled big time. I double checked the power pod and it's good just need to check the aileron that got bent. It moves by hand ok. I will be triple sure before I fly it again.
Dunfielder
Active member
I can set up high and low rates on my TX. Currently low is 70% rate 50% expo and high is 100% rate 30% expo. All this flying was done on low rates. I didn’t even think about high! I believe I have too much throw on the ailerons because the low looks close to 12 degrees high looks like 16 or so. Probably need to fix that.
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