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Old May 28, 2014, 02:54 PM
Southern MN USA
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Joined Jun 2012
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thanks, john. I'm sure I will have enough power. I set out for the maiden yesterday but she never even got off the bench. it seems that one of the main retracts has failed. the good thing is that it is stuck in the down position. as I was doing my pre flight I lowered the gear and the one main gear just kept running! when it stopped it stopped.i removed the retract and fiddled with it a little but there is no response no matter what I have tried so it will have to come apart or just fly it with gear down.
another set back.
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Old May 28, 2014, 07:35 PM
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Arvada, Colorado
Joined May 2004
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Errr, Nuts!

It's disappointing to hear about the landing gear problem, but looking on the bright side, it's better to discover it on the ground than when coming in for a landing on a low battery or worse!

A quick question: how does the Krylon flat paint bond to the Guillow's plastic? Did you spray it directly from the can; or pray it into a jar and apply it by brush? The canopy looks superb, your patience with the xacto knife and tape really paid off handsomely.

Best regards, Chris
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Old May 28, 2014, 08:31 PM
Southern MN USA
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Joined Jun 2012
352 Posts
thanks Chris, I'm thinking of just going with some new main retracts and be done with the problem. I will have to solder a connector in on each side and then the new units will just plug in and bolt on.
about the krylon, I did spray it right from the can on the canopy BUT it did sort of warp it as it dried. the edges sort of twisted up in the leading edge part of the canopy so i wrapped it with a rubber band and it sort of laid back down. it looks good but the original fit before the paint was perfect. yes it bonds terrific.
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Old May 30, 2014, 01:40 AM
Southern MN USA
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Joined Jun 2012
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the exploratory showed that there is a problem with the switch board in the retract. I will have to search out another one or just use some plastic body with metal trunion units. I had a good plastic trunion unit that I used to test the wiring with as seen in the pictures. i'll see what I can come up with.
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Old May 30, 2014, 08:49 PM
Southern MN USA
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Joined Jun 2012
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well, I just had to see how she flew. just a week ago the city cleaned the debris field from the metric tonnes of snow that was stored there and I had my test strip back. =D. I removed the gear doors and decided to fly with the gear down as the left unit is stuck down. a storm front was coming through so I wanted to take advantage of the calm air but wouldn't you know it the wind changed to cross the runway as I was flying but it ended up being no big deal as she flew right down to a crawl without stalling.so I put her in the tall grass and ended up with just a bent nose strut no problem.
I will be flying her again soon and trying to ring it out a little. the power isn't bad but I was really expecting more. the handling is excellent just a real joy to fly no pucker factor, no terror, very steady and forgiving. ground handling is great. the battery had 391 in each cell at the end of the flight so I think there is another minute or more in there for future flights.
Guillows P-38 R/c conversion maiden flight (5 min 47 sec)
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Old May 31, 2014, 07:15 AM
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United States, TX, Houston
Joined Sep 2003
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Meltor - thanks for linking this thread from the "show your warbirds" one, I really enjoyed going through your build pics and descr!
Although I'm one of those lazy SOBs that likes the convenience of plug-and-play foamies (with a few mods ) I very much appreciate the skill and patience it takes to build one of these kits.

Are these the retracts you have?
http://www.hobbyking.com/hobbyking/s...arehouse_.html

I almost ordered a set to use the mains for the F-82 I'm building from two Durafly kits, but ended up going with the "old standbys" just because something about the metal ones struck me as odd
http://www.pw-rc.com/product_info.ph...806d0a4e3648d0

I'm using them on my 1.5m foam P-38 that has over 40 take-offs/landings and surely well over 100 cycles from all the touch-and-goes and bench testings with zero failure.

BTW when I bent 4mm rod for the gear struts I put an extra couple bends so it "follows" the top of the wheel, and the vertical part is centered with the tire. Looks a little more scale and hasn't proven to be a weak point. But since you've already offset your gear to one side it's probably too late to do with yours.

best of luck on all future flights!! Nothing looks as amazing as a P-38, and both of the one's I've had have been super sweethearts to fly.

cheers
Kurt
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Old May 31, 2014, 10:58 AM
Southern MN USA
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Joined Jun 2012
352 Posts
thanks kurt, those are the retracts from hobby king. I liked the scale speed that they had and thought that they would be very durable. I was just looking for one main instead of a full set. I'm sure that one will turn up .
I like the plug and play foamies too! the UMX Pitts is one of the best flying most fun plug and plays I have ever bought.
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Old Jun 06, 2014, 11:28 PM
Southern MN USA
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Joined Jun 2012
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after just a few flights it is apparent there isn't enough power for aerobatics and flight times are lacking. . with the 2200mah 2s battery it will cruise the plane around just fine but flight times are hardly 4 min.i tried a 2800mah battery but could hardly notice the difference in flight time and I really could tell the extra weight. so my next move is to try smaller props and a 1500mah 3s battery I will test it with the watt meter as even with the 2s setup it is really pushing the 18 amp escs. I hate to have to find some other motors and esc's but I'm always open to suggestions.
I did end up going with another set of retracts from hobbyking. these have functional struts and the retract units are the same as I won on ebay last winter so they bolted right in. thanks kurt for leading me in the right direction on the retracts they aren't perfectly scale but they work great .
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Old Jun 06, 2014, 11:45 PM
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United States, TX, Houston
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oooh those struts look nice!
FWIW my 1.5m 1.9kg P-38 flies great with a little over 1:1 max thrust from 2x3530 1150kv motors with 9x7 three bladed MA CR props, 40A Turnigy Plush ESCs and 2700mAh 4S Zippy Compacts. I did just burn out a motor though, am waiting on higher rated 3536 1000kv'ers from HK now.
I typically fly at 50-70% throttle, reserving WOT for big loops and catching up to gassers when my ego gets the better of me... 5 minutes is a little shorter than I'd like but burns through ~75% of the tight fitting Zippy Compacts so that's all she's got.

I forget how big and heavy yours is but unless it's pretty small and light 3S/2200 sounds about right. There's not a lot of room in the nose of a P-38 to fit a big pack when you're running with a retractable nose gear (personally I wouldn't have it any other way. Takeoffs and landings are just so much fun). Hopefully you can work out a satisfying mix of power, flight time and weight.

keep us posted!
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Old Jun 07, 2014, 12:01 AM
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United States, TX, Houston
Joined Sep 2003
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Another thing - just noticed that those props look quite big in relation to the airframe, at least bigger diameter than the MA 3-blades I'm running with a 1.5m span. Closer to scale yes, but have you run various prop/motor calcs?
If not here's one to try: http://www.ecalc.ch/motorcalc.php?ecalc&lang=en
They don't have all that many motors (at least not all of the HK ones that I seem to check lol) but it's interesting to see the effects of prop brand, diameter, pitch, # of blades, motor KV, battery cell count, C rating etc have on watts, amps, thrust, pitch speed, max prop RPM etc.
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Old Jun 07, 2014, 09:01 PM
I'd rather be flying.....
United States, IA, Story City
Joined Oct 2013
335 Posts
Hi Meltor -

Glad to see your fantastic p38 in the air !

I'm sure you can find that " sweet spot " of power and duration with the power system you have....

Best Regards,

Jeff
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Old Jun 07, 2014, 11:51 PM
Southern MN USA
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Joined Jun 2012
352 Posts
thanks Jeff, I worked on my power system today and cut down a pair of 8"props to 6 7/8" and tried a 3s 1500mah 25c battery. it made 416 watts @ 43 amps! but the cool thing is that @ 2/3 stick it makes as much as the 2s setup made @ wot and @ less amps ( the 2s setup went 277 watts @ 38 amps). I will really have to watch it as to not pop the 18 amp escs and will eventually replace them with some 25 amps. I'm testing for flight duration tomorrow and will bring the heat gun to check motor temps. I'm thinking I should cut the props down to 6" but I want to get away with all of the prop I can for now.
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Old Jun 10, 2014, 11:08 AM
I'd rather be flying.....
United States, IA, Story City
Joined Oct 2013
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Yes better safe than sorry on those ESCs... that 38 look s great...

Best Regards,

Jeff
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Old Yesterday, 07:09 PM
I can crash anything
United States, TX, Fort Worth
Joined May 2012
143 Posts
I just found this build log, love it. Any update, how did the new prop/battery combo work?
Jimmy
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Old Yesterday, 09:52 PM
Southern MN USA
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Joined Jun 2012
352 Posts
hi, I've been flying the p-38 with a 1500mah 3s battery and I cut down the props to 6 3/8" she flys great with the 18 amp escs. I just go easy on the throttle and am having no problems. the flight times are right @ 4 min. leaving 370 per cell. my daughter put together this video of some of my guillows conversions and there is some more flight footage of the p-38 at the end.
I hope you enjoy it!
My Guillows rc conversions (3 min 29 sec)
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