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Firefeather Rocket Glider/DLG/Hotliner

wilmracer

I build things that fly (sometimes)
Mentor
#42
Absolutely! It takes everyone a bit of time to glue everything back together between rounds :D
Cool! I'll have to see if I have anything to fly in the combat. Not sure what time I'll make it out there. Likely not until close to noon. I really want to get the P-40 tuned up before the giant scale fly in. Still not sure I'll be able to make it, but if I can I really want to bring it out to that event. It would be a great place to debut the FW-42 too :p
 

rockyboy

Skill Collector
Mentor
#44
I really want to get the P-40 tuned up before the giant scale fly in. Still not sure I'll be able to make it, but if I can I really want to bring it out to that event. It would be a great place to debut the FW-42 too :p
Good plan - I just put the second cowl fiberglass into the mold yesterday, and have a revised plan for balancing using the new pergola I put up in the back yard a couple weeks ago. Finally - some place big enough to assemble and hang her for balancing in one piece! :D
 

wilmracer

I build things that fly (sometimes)
Mentor
#45
Good plan - I just put the second cowl fiberglass into the mold yesterday, and have a revised plan for balancing using the new pergola I put up in the back yard a couple weeks ago. Finally - some place big enough to assemble and hang her for balancing in one piece! :D
Cool! And feel free to share your build in this thread too. You're far more experienced with balsa building than I am so your input will be great.

As for my build, I'm cursed with micro stuff. I had the small FRSky receiver break on me last week and I'm awaiting a new one. The new servo block is installed and ready to go, so the receiver is the last piece of the puzzle. I wouldn't have been able to fly her on Saturday anyway. Winds at Lorton were close to 17mph sustained with some REALLY ugly gusting. I did two flights on the P-47 to see how I was feeling about the conditions before getting the P-40 out. On the second flight the gusts were so bad that I barely made it down in one piece and managed to crack the cover for a wingtip nav light. Fortunately no more damage than that, but that was enough to convince me to leave the Warhawk in the trailer. Although it wasn't on radar I can now confidently say that she HAS made it to triple digits with the help of that crazy tailwind :)
 

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wilmracer

I build things that fly (sometimes)
Mentor
#46
The curse appears to continue. Got the new receiver installed lat night and was working through setup and throws. Everything worked great for about 30 minutes and then the elevator servo failed. I wondered if the spring was putting to much continual load on it, but I know @FAI-F1D uses a similar setup and the spring doesn't feel THAT strong to me. There was some chattering that seemed to occur as I moved the servo lead cables around as well but I addressed that by securing the cables so they didn't shift. This time I did NOT re-crimp to keep the leads as clean and short as possible. I've already validated that the voltage from the integrated BEC is appropriate, but IDK what else could be causing so many failures. I've had failures with and without any load on the servos. I'm running a Castle Creations Talon 15 that is providing a steady 5.5v @ up to 8amps. The servos are spec'ed for 4.8-6v. They do make it clear not to run more than 6v, but I'm NOT doing that. When I have time I'll be hooking up the ESC to the programmer again and I'll see if I can drop the voltage to 4.8, but I don't think that is an option on this model.

This is starting to be reminiscent of my experience with the Libelle a few years back and the Hitec submicro servos they recommended. That is a larger model and I ended up swapping in larger, stronger servos, but I don't think this model would do well with the extra weight (or if they would even fit).

I'm not about to give up, but I had hoped to have this knocked out by now and not be spending time chasing gremlins. I guess that is just part of the hobby :confused:
 

wilmracer

I build things that fly (sometimes)
Mentor
#48
Ugh - that's annoying! Are you using the Blue Arrow 3.4g servos? I just placed an order yesterday for those... :unsure:
It is these https://hobbyking.com/en_us/blue-arrow-3g-high-speed-digital-mg-micro-servo-50kg-06sec-60deg.html

Again I don't know if it could have something to do with the BEC voltage or perhaps I don't have the gentle touch needed to make them work. I really thought I was over the hump when I was able to start programming throws and adjusting the mixes. If I'm lucky I'll be able to get this servo off without damaging the others.

I have a few spares now. I may consider NOT gluing them together and attempting to do a standard servo tray so that replacing individual servos doesn't require extensive surgery. We'll see though. I am in the middle of another cram session for another certification and may not be able to work on any toys this week. Still hoping to get out to Lorton on Saturday if the weather cooperates and get the P-40 up. Still looking pretty windy though :-(
 

rockyboy

Skill Collector
Mentor
#49
Yeah, I think that's the same servos that I ordered based the kit recommendation, but I think I'll be using a SkyPower 10amp esc and Emax 1806 cause I have those in the drawer already. Thinking a servo tray is in order with all the troubles you're having.

I'm planning to get to Lorton on Saturday too for some combat and re/maiden flights. Seeing 7mph winds on the current forecast which isn't too bad...
 

wilmracer

I build things that fly (sometimes)
Mentor
#50
I'm planning to get to Lorton on Saturday too for some combat and re/maiden flights. Seeing 7mph winds on the current forecast which isn't too bad...
I may not be looking at the right forecast for Lorton and I was just using wunderground but I saw 12 and figured it is usually a bit more windy up on that hill. Fingers crossed! I am thinking it will be close to 11 when I get there.
 

wilmracer

I build things that fly (sometimes)
Mentor
#51
Back to the firefeather. After some additional testing this AM I'm pretty confident that the servos for the flap/ailerons are OK (if not PERFECTLY aligned... I'll fix that with software adjustments). The servo for the elevator hadn't completely failed, but was buggy enough that it would eventually kill the airplane.

I went digging in the old servo drawer and found several eflite s75 servos that are a few grams heavier and aren't MG, but have been reliable in the past and have much more umph. I swapped out the elevator servo with one and it fits perfectly and has much more authority on the elevator.

IF an aileron servo fails I'll rip all three out and add the other two s75. At this point I'm only sacrificing about 3g to use the single larger servo. They would fit if needed and I'm confident I could ditch the excess wiring and crimp these to the right size, so a full "upgrade" to these would probably be around 9-10g AUW. Might be worth it for the piece of mind. We'll see though.

Back to work now. Pictures tonight. FWIW the folding prop may have just been shipped so it could be another week or two before that that shows up here. Hope it comes in before FF.
 

wilmracer

I build things that fly (sometimes)
Mentor
#52
ok... so got it setup with just the one s75 servo, got the pushrods installed, and started setting up throws. Right aileron/flap servo failed 10 minutes it. All servos removed and the a block of the s75 servos has been installed. I had to make some changes to the fuse to make it work. I cut out the servo slots, back filled them with balsa, and then cut new recesses in to clear the new servo arm locations. I'll go back and add a bit of white covering material and it will blend just fine.

Pushrods installed and got the basic setup done. I'll be tweaking throws and the mixes when I get a chance. I was about to take her out for a few test glides but it just started raining here.

Getting closer now at least!
 

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rockyboy

Skill Collector
Mentor
#53
Good grief! Not feeling good about throwing some $30 towards HK for a bunch of these Blue Arrow servos earlier in the week...

Glad she's all together and working correctly now! :D
 

wilmracer

I build things that fly (sometimes)
Mentor
#54
Good grief! Not feeling good about throwing some $30 towards HK for a bunch of these Blue Arrow servos earlier in the week...

Glad she's all together and working correctly now! :D
So it is entirely possible that I am just not delicate enough with my... umm... technique. It is still possible that the 5.5v from my ESC's BEC is too much (although it SHOULDN'T be). Or maybe it didn't like the combo of the receiver/esc/battery I used. I used gel CA to avoid it bleeding into the servos and hit them with accelerator, but maybe I was still getting CA inside the servos. Remember that plastic strap is what holds them closed.

I have no idea why I killed so many but, again, no one has ever accused me of having a gentle touch. You've got a LOT more experience than I do working with balsa birds around this scale. I suspect you'll have no problem at all. I'll just have the heavy one at FF ;-)
 

rockyboy

Skill Collector
Mentor
#55
I'd think if the CA was a problem it would have showed up right away - but I killed a couple servos with thick CA, and then a few more with Gorilla Glue, before it sunk into my head that servos get hot glue only. Anything else is rolling dice that aren't weighted in our favor. :cautious:

I do wish I could find a better listing of servo sizes and powers so we could find alternatives though. http://www.headsuphobby.com does a great job with testing motor/prop/battery combinations, but I haven't found anything like that for servos.
 

wilmracer

I build things that fly (sometimes)
Mentor
#56
@FAI-F1D

Planning to do some glide testing this afternoon. Any advice on the right CG? I can obviously just play with it until I get a glide I like, but I'd love to know where yours is located. I'd also be curious about your AUW sans rocket and if you typically leave a spent rocket case in so as not to change the CG.
 

FAI-F1D

Free Flight Indoorist
#57
If I remember correctly I was around 40% root chord on the CG. I generally fly without a spent casing aboard. In general it's not likely to come out tail heavy. ;)
 

FAI-F1D

Free Flight Indoorist
#58
I was reminded recently that HK has been known to get knockoffs of name brand servos in addition to their tendency to obtain the ones that didn't get all the QC checks. This could be the problem. It is possible that a bad batch is the issue as well. I've got a lot of flight time on that particular make/model and found them to be quite rugged, so this is very disconcerting.
 

wilmracer

I build things that fly (sometimes)
Mentor
#59
I was reminded recently that HK has been known to get knockoffs of name brand servos in addition to their tendency to obtain the ones that didn't get all the QC checks. This could be the problem. It is possible that a bad batch is the issue as well. I've got a lot of flight time on that particular make/model and found them to be quite rugged, so this is very disconcerting.
I'll grab some up close shots of the ones I've got tonight and you can let us know if they jump out as wrong. I think Rockyboy has some on order as well so I'll be curious if he gets the same thing I did. I know you wouldn't trust your demo models to iffy hardware so I figured you hadn't run into issues before.

I had her out at the field on Saturday and hoped to do some trimming and tests, but it was WINDY again. 10+ pretty much sustained with some heavier gusts. It was actually strong enough to lift and tear my canopy. I got REALLY luck that when it flipped it missed both the P40 and the P-47 that were sitting under it. It did launch an ammo canister that one of the lines was tied to about 20', kindof like a trebuchet. I figured it wasn't the best opportunity to trim her out. Still have a few weeks before FF so I'll get a chance soon.