Heinkel P.1076

[saiga556]

I have been planning to scratchbuild a Heinkel P.1076. I have started doing some prop testing using my FT Mustang because the Heinkel will be about the same size, just sleeker.

My mustang uses a Mantis 35A ESC, a Suppo 2217/7, and 3s 2200mah batteries.
I will give my impressions of the different props I have tried.

APC SF 9x4.7, good all around performer
APC E 8x6, better speed than all the others not as much thrust
APC E 9x6, all broken but based on past use might be a good choice
Master Airscrew 9x6, looks the best, good performance but seems like shorter flight times
HK 10x5 (link) over propped not good performance
GWS 8x4x3, Three blade. no speed or thrust. not good

So far the apc 8x6 is winning. I would like more speed for the mustang and definitely for the Heinkel. What prop do you guys think I should try? Maybe I need to jump up to 4s?

 

[saiga556]

Here is what I have in sketchup so far. for some reason I cant get it to unfold the way I think it should. I'm about ready to give up on sketchup and just wing it with the ruler and knife.


Any suggestions are very welcome.

 

[rcspaceflight]

Looking good. For unfolding it, I always make a copy of the plane, "explode" the entire thing, and then copy and paste each wall/side. I take the walls/sides and rotate them so they are flat on the ground. I "group" each side so they don't stick to each other, and then snap them side by side. Then I force the 3/16" gap for the A and B folds.

Rotating the pieces can be a pain. I find that if you have the red/blue/green lines between the camera/view and the piece you're trying to rotate, Sketchup is a lot more likely to snap the rotate tool to the red/blue/green axis. Pick two end points of the piece and snap rotate it to the red/blue/green axis so it's flat. After a few rotations you can get any awkwardly rotated piece to end up perfectly flat. Ungroup and then regroup the piece to double check that it's flat.

 

[saiga556]

Thanks for the advice. I tried the easy route with an unfolding tool and couldn't get it to work right. I wish I had a copy of autocad to use as I have had some schooling in its use and I am much more familiar with how it works.

As far as building the plane I'm not that worried about planning every little thing. I am most concerned with the performance of the aircraft. Obviously this plane was built for speed and I need to figure out the most cost effective and efficient way to get that speed. It seems like my mustang is slower than I thought it would be and I feel like I'm missing something that I need to figure out before getting too deep in this new project.

 

[rcspaceflight]

If all you're after is speed, then it depends on your power set up. I really like this static thrust calculator. It's only an estimate, but gives you a really good idea of the top speed that could possibly be produced with a propeller at any given RPM (Kv times Volts).

I know from it that my 2200kv motor on a 3S with a 5x5 prop should see a top speed of over 100mph. But only 400grams of thrust.

 

[saiga556]

Maybe I need a higher kV motor for both applications.

Anybody know what the forward swept wings will do to stall speed and tip stall? I'm hoping that the tip stall will not be increased so I don't have to run uundercambered tips.

 

[nerdnic]

Hey man, looks good so far. For more speed you really need more motor. The plane design has a lot to do with its full potential but the motor, esc, and battery are prerequisites and the motor you have just isn't going to get you over 40mph or so.

Check the link to my Clipped wing Spit and Mustang in my signature to get an idea of the power you need.