Techone Pulama EPP Bi Plane Assembly Log

[fudge2k85]

Bought a Pulama Bi-Plane from Jethobby over lunch. Initially I was looking for a micro plane, but settled on this one instead. After all, I've been wanting a bi-plane for some time.

Last night Managed to just do parts inspection and survey, as well as mounting the motor on the plane. Set-up is as follows:

1. JH2812 (1534KV) Motor
2. 18A ESC (this was from quite some time back... think it's ESky)
3. DN Power 25C 800mAh 7.4V LiPo
4. 9x5 folding prop

As you can see from the pictures, everything is included except for electronics. Carbon rods, landing gears, hinges, clevis, etc.

The instruction manual was relatively clear, with pictures as guides for every step in good English. Nice. But here's a reccomendation: read everything first before starting to assemble. It'll give you a rough idea of time reuirement.

[fudge2k85]

By the way, reccomended set up is for a 1100kV motor with 3s on 12A. Since I'm trying to reduce the weight, went with mine instead. Calculated to have roughly the same power output anyway.

Hmm, anyone else with the Pulama, btw? Can share your experience with this bird? Is it slow enough to really fly indoors?

[fudge2k85]

Managed to dry fix everything over the weekend (slow to post... 1 week delay... lol!!). Noticed one problem for the build: No service bay! lol! Looks like I got to carve one out over this weekend.

Managed to install all the carbon strips/rods onto the parts and fixed up the rudder and horizontal stabilizers as well as the elevators. Managed to install the servos as well. Maybe over this weekend, I'll complete it. I doubt I'll have time to maiden it, though. Got to tie up a few things at the CC for the next funfly (14th August 2010).

One thing to note: The hinges supplied are fantastic! lol!! lightweight and easy to install as well.

Very happy with this kit overall.

[fudge2k85]

oops... forgot the photos...

[fudge2k85]

Tested the power system today. MISMATCHED! When I pull the throttle on my tx, the motor won't move. Hmpf! I wonder if anyone here knows how to program an e-sky ESC without the programming card? anyone?

[durex]

Bro, this is a very good plane for indoor flying....built it light. Mine is powered by cd-rom motor, 6-amp esc, 9x6 gws HD prop. Batteries are 2-cells 7.4V, 350mAh. Can fly for 5mins +.Happy flying

[fudge2k85]

Bro, this is a very good plane for indoor flying....built it light. Mine is powered by cd-rom motor, 6-amp esc, 9x6 gws HD prop. Batteries are 2-cells 7.4V, 350mAh. Can fly for 5mins +.Happy flying

Ahh, crap. I think I'm overpowering my plane then. Hmmm, maybe that's why I'm facing some CG issues...

Thinking of changing the foldable prop to a normal plastic 9x6 prop due to CG issues (too nose heavy!!). Thinking of other ways as well, like moving my battery pack even further back and parelleling up my 2 lipos. I kinda like the foldble prop a lot. Alex (viper1990) reccommend I do a glide test just to re-check my CG. I'll have to wait for the ca to cure first on my landing gears (maybe tonight if I have time).

Went over again to JH over lunch on Thursday to get a new motor. Got the EMP N2822/24 (1400 kV). Motor matches the ESC and LiPo well. Did a rough calculation. Theoretically should give around 130W of power. Get 80% efficiency would be around 100W. For a 500g plane, that's not too bad, I guess.

Did a static time test and motor runs for about 3+ mins. Basis of time test is full-throttle (about 10s) followed by 75% (estimate) throttle to simulate actual flight power usage, with 9x6 foldable prop.

[fudge2k85]

Some problems surfaced when trying to maiden the plane. The motor would need full (extra possibly as I had to trim up the throttle channel) power to start up. Once the motor's running, all's ok. So after the last checks, tried to start up again the motor from a full stop and then.... the motor doesn't spin. Initially tought its a connection issue, so checked all connections. Found out that the connections are all ok.

Thankfully, the other bros were on hand to help diagnose the problem. Bro Loyn suggested removing prop and the motor worked beautifully (as per bench tests). When the prop was put on the motor, stuttering occcured. When we loosen the prop a bit, then the motor works fine. Bros there call it the "tightening effect". Sianz. Looks like I have to go change ESC again.

Pulled out an old 12A esc i have lying around. Still NIP (never used... never thought I would one day use low amp draw... ). Will do some bench tests on it over the weekend and see how it goes.

[fudge2k85]

The CG problem I was grappling with had a simpler solution; changing battery location. Looks like I need to do a bit of hacking. Either that or I have to change my motor (again).

Initialy used ballast weights on the tail but was told by other bros there (Crafter, Loyn) that I should keep it lighter if I want to keep it indoor-flyble. Oh well, looks like my first foray into indoor is plagued with so much problems for the power system set up.

So much so that I didn't manage to maiden it as planned earlier.

[fudge2k85]

Solved the CG issue without hacking! At least it seems that way, based on the manual's CG. So I guess have to try it out on Sunday.

The solution? Simple. Just remove the ESC. So how does the plane fly without an ESC? It won't. But it will fly with a motor WITH built-in ESC. Hopped over to Aerosmith and got me one. Motor itself was smaller than the same motor I had previously (even with a built-in ESC!), so I shaved about 20grams from there. This is before deducting the ESC, which is around another 10-20 grams I would say.

There you go! Power system matching and CG issue solved by 1 simple solution.

I don't really like my throws, though. Uploaded a video with it. Can anyone help me see if it's ok?

[fudge2k85]

oops... here's the vid..