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Old Nov 04, 2012, 01:58 PM
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No i have intake ring on both fans. Anyway problem solved. Not sure which 2 changes did it but it flies now
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Old Nov 04, 2012, 02:13 PM
Do it Right, the first time!
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No i have intake ring on both fans. Anyway problem solved. Not sure which 2 changes did it but it flies now
Glad you sorted it out. What 2 changes?
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Old Nov 04, 2012, 03:45 PM
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Bigger fsa on tube and took out intake diverters. But with one thing fixed comes another problem. Plane did not want to roll right unless going very slow . At full throttle it would not roll right at all. Ended up doing a banked to the left nose in as i couldnt get it to level out. Rolled left fine at any speed. Elevons were level and did a preflight check. What could cause this? Also of note i didnt have this problem with the dynam fan. I thought maybe the servo got over torqued and stalled but why would that only happen on right turns and not left? I've had this happen before on a pusher prop jet, but I always attributed it to torque roll from the prop at full throttle. Didn't think there was torque roll with an edf as the part thats spinning isn't directly attached to the plane like a prop is. This is now the second time I've crashed this plane today. I am glad that I decided to figure out this power system in a profile jet as opposed to the f15.

Edit: Well still not sure what the problem was. I drank a couple beers and added some ailerons. Kinda ghetto rigged it in about 30 minutes. Plane looks like frankenstein. Anyways, had the gf drive me to a field to give it another shot. I refused to end the day with a crash, although honestly I didn't expect it to even fly after all the glue and tape I had to add to put the puzzle back together. Anyways, tossed it up and away it went. I guess I have the ailerons misaligned as it was all over the place. I somehow ended up doing a high alpha a few feet off the ground and thought it was going in. Somehow I gained some speed and got some altitude. It actually flew fairly well except for the fact that I had to constantly give it aileron correction as it was wanting to roll left constantly. Ended up getting a good landing. I think I will be leaving the cs in this plane and finishing up the F15 with the dynam fan. My goal is to get the F-15 finished tomorrow. I'll get some pictures up as soon as its done and also give a succesful maiden report hopefully. I'm now debating on whether to add ailerons to the f15 after the hassle from today.
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Old Nov 04, 2012, 09:05 PM
Do it Right, the first time!
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Maybe you kow this already?


http://www.rcgroups.com/forums/showp...postcount=5627
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Old Nov 05, 2012, 07:30 AM
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No i didnt know that. Thanks for that. I was at 51mm on thrust tube originally and it didnt fly. Much better at 56. Maybe ill open it some more
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Old Nov 05, 2012, 11:13 AM
Do it Right, the first time!
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stingeragents Not trying to second guess you here, but in the CS 70 thread you mentioned that---

" I saw one guy that cut a cheater hole in the exhaust of his foam plane and it gave it a better sound. I'm unsure if I should cut a hole in the bottom of my thrust tube." Are you sure that it wasn't on the intake side?
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Old Nov 05, 2012, 11:31 AM
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Nope. It was definitely on exhaust. Was a t45 and he put it about 3 inches before end of plane. Video is in that thread. Believe it was titled who needs a turbine.

Edit: here
HK T-45 cs10 fan 6s BL-32 motor 6s 3000 Who needs a turbine. (4 min 48 sec)


Edit 2: Just as an update, got a lot of work done on f15 today so far. Got the elevators fiberglassed on, all electronics put into place. Soon as the fiberglass dries ill hinge the elevators. Then all thats left is gluing the wing and strake pieces on.
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Old Nov 05, 2012, 03:37 PM
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Well got everything together. Will wait until tomorrow to maiden
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Old Nov 06, 2012, 02:02 PM
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Flight report. Well had to build a small handle on bottom of plane as it was too wide to hand launch as is. Throttled up to about 3/4 and let her rip. Had a slow but straight climb out. Next to no aileron control until it picked up speed. Running elevons only at the moment with 100% dual rate and 120% epa. As it slowly picked up speed I gained a bit more aileron authority. First thing to my mind as I let go of the sticks. It needed 0 trim and it was perfectly stable. Felt like flying a trainer plane. It was going rather slow at 1/2 throttle, maybe 30-40 tops, so as I made the first circuit and turned back around I advanced up to full throttle. Didn't sound as if the fan was spinning any faster. Held it at wot for about 5 secs and then the motor cuts out, crap. Made a quick left turn and pointed the nose down to maintain momentum. Glided it to the ground with only a soft thud. My hand launcher was only thing that dented a tad. So as I walk over to the plane and pick it up to check for damage, I give it a bit of throttle and it works. Hrmmm. It wouldn't turn back on in the air. I start thinking low voltage perhaps, but when I got home to charge up the 4s 2200 pack, it was at 16v still and only put back in 250mah, so that can't be it. Only thing I can think is the battery may be bad. Its had a crash before and is a bit dented in the front. Balances fine up to the correct voltage so not real sure on that. It is the detrum 70mm fan/motor/esc combo from hobbypartz which was working fine in another plane. Any takers?

Edit: I have no watt meter unfortunately to test the battery with a load on the ground. Went back and redid esc programming just to make sure it wasnt messed up. Well i guess my next step is to fly it with a different battery. If that works guess ill toss the other one
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Old Nov 06, 2012, 04:50 PM
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Originally Posted by stingeragents View Post
Flight report. Well had to build a small handle on bottom of plane as it was too wide to hand launch as is. Throttled up to about 3/4 and let her rip. Had a slow but straight climb out. Next to no aileron control until it picked up speed. Running elevons only at the moment with 100% dual rate and 120% epa. As it slowly picked up speed I gained a bit more aileron authority. First thing to my mind as I let go of the sticks. It needed 0 trim and it was perfectly stable. Felt like flying a trainer plane. It was going rather slow at 1/2 throttle, maybe 30-40 tops, so as I made the first circuit and turned back around I advanced up to full throttle. Didn't sound as if the fan was spinning any faster. Held it at wot for about 5 secs and then the motor cuts out, crap. Made a quick left turn and pointed the nose down to maintain momentum. Glided it to the ground with only a soft thud. My hand launcher was only thing that dented a tad. So as I walk over to the plane and pick it up to check for damage, I give it a bit of throttle and it works. Hrmmm. It wouldn't turn back on in the air. I start thinking low voltage perhaps, but when I got home to charge up the 4s 2200 pack, it was at 16v still and only put back in 250mah, so that can't be it. Only thing I can think is the battery may be bad. Its had a crash before and is a bit dented in the front. Balances fine up to the correct voltage so not real sure on that. It is the detrum 70mm fan/motor/esc combo from hobbypartz which was working fine in another plane. Any takers?

Edit: I have no watt meter unfortunately to test the battery with a load on the ground. Went back and redid esc programming just to make sure it wasnt messed up. Well i guess my next step is to fly it with a different battery. If that works guess ill toss the other one
I would think it might be your esc started to over heat and shut down. You might want to install an external ubec to be safe. Could solve your problem by removing some heat. Also check all your solder connections. I would do a full test on the ground. Get two hair dryers and blow cool air into the ducks while running the motor and see if the motor cuts out on you again. Move your sticks on all your control surfaces along with different throttle ranges as if you are flying. Do you have the esc in the airflow for cooling? How long was your flight? Was your battery warm or cool to the touch upon landing? Did you check to see if the esc was hot?

Try your new battery pack on the ground as suggested above. You should also be able to use a bigger battery pack. Another reason to get a watt meter so you know what size (mah) and "C" rating battery pack will be your best fit for performance.

If you plan to build any more planes I strongly suggest you get a watt meter. Just because the system worked fine in one plane does not mean it will in another. You could be pulling more amps as the air needs to pull further through the ducting.

Jet looks good! Like to see the final paint job pictures. Have you painted her yet or are you test flying before painting?
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Old Nov 06, 2012, 05:51 PM
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Will paint but want it sorted out first. Ive actually been scratch building for almost 6 years.just never got one. I only recently started scratch edfs though. I dont think it was heat as it was a 1min flight tops. It only drained 250mah from pack. I did a ground test with same batt recharged but without the hair dryers. Ran fine for like 2 mins with several wot run ups for about 5 secs. The esc isnt in fan airflow but it is in the intake airflow beside the fan. Intake isnt sealed.i know people use this setup on 5s no problem and im running 4. I dont think the larger intake issue is the prob because of this. I will check my solder connections and refly with same batt. That way i will know if the soldering was issue or not
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Old Nov 07, 2012, 03:09 PM
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Ok. Checked my solder connections. All good. Went to fly with a different battery. 4s 40c 2200. Flew good for about a mibute and half and it shut down again, this time at like half throttle. What the heck is goin on here. I thought for sure it was the battery but that obviously cant be it. It can't be overheating after only 1 minute. The ESC does have airflow across it. The last plane this setup was in, a profile F-22, never had this issue at all, so I'm fairly stumped. I didn't change anything about it when I pulled it from that plane to put it in this one. I still have full elevon control so it can't be a signal loss thing. The battery was full charged as well. Hrmmmm. I have no clue.

Edit: Ok, I have found a way to replicate the problem on the ground. I was holding the plane up vertically to see if I had over a 1:1 thrust ratio. I throttled up to about 3/4 throttle. After about 4-5 secs the motor cut off. I dropped the stick and had to wait about 1-2 secs before it would start again. I did it again, and same exact thing.
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Old Nov 07, 2012, 04:51 PM
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Mystery solved. I pulled off the wing to look at the battery wire and instantly realized what i did. I extended the battery leads and only used like 16 gauge wire. The positive side showed burn marks as well as the insulation melted in several areas. I unextended the battery side and resoldered it all . Problem solved. Lesson learned is dont extend battery leads and use big enough gauge wire
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Old Nov 08, 2012, 01:12 PM
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Mystery solved. I pulled off the wing to look at the battery wire and instantly realized what i did. I extended the battery leads and only used like 16 gauge wire. The positive side showed burn marks as well as the insulation melted in several areas. I unextended the battery side and resoldered it all . Problem solved. Lesson learned is dont extend battery leads and use big enough gauge wire
Nice to hear you figured it out. Waiting for you final paint job and flight video footage.
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Old Nov 08, 2012, 01:48 PM
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Will do. Had to order some wire so waiting on it.

Edit. Wire should be in today so I can get this bird fixed. I was also looking at the front of it and since I did the 118%, my intakes are way too big for a 70mm, and I think it is giving me a lot of drag. I've been working on doing some partial internal ducting so that I don't have free flowing air going past the fan. Also working on shrinking the intakes by angling down the top of the intake cover a bit.
Edit 2. All back together. Did a few bench tests like before and running good. 40mph winds today so no test flight
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