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Old May 29, 2011, 10:43 AM
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Originally Posted by turboparker View Post
Finally, a windless morning - and it's not raining! I decided to try some ROG takeoffs from my deck. 5043 prop w/Hyp 180 cell. #3 keychain cam attached to my hat.

The stock motor is on its way out. She's hitting SLVC when the 180s are at the 60% discharge point. Time for the SX motor transplant!

Joel

http://www.youtube.com/watch?v=_6gzfpv1Hv4
That backyard is a park! Yeah, looks like your motor is dying. No unlimited vertical.
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Old May 31, 2011, 02:00 PM
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Originally Posted by dataylor57 View Post
You might want to look at some of the EPP foamies, still light but more durable than the Eflite Extra. I have the 3D Hobby Shop EPP Extra, it will 3D very well.
I ended up building this instead for much less than the UMX Extra:


Build-up 074 by bryanewyatt, on Flickr

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Just go for it! You won't regret it and...........you can never have too many planes in the hangar
Somehow I think my wife would beg to differ.
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Old May 31, 2011, 02:27 PM
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Originally Posted by bill clark View Post
econd flight added some SfG's and LEE's. now thats alot better
Sorry to dredge up an old post, but can you explain how you made those? I'd like to make some clip-ons for another plane, and this was the only time I could recall seeing removable units in play.
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Old Jun 01, 2011, 01:33 AM
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Hi, anyone knows cheap source for 4mm adapters with cheap posting to Europe? I was looking at http://www.microflight.com/Online-Ca...dapter-Set-4mm, but I dont like idea of paying 16$ for a tiny piece of plastic.
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Old Jun 01, 2011, 09:56 AM
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Originally Posted by dziedrius View Post
Hi, anyone knows cheap source for 4mm adapters with cheap posting to Europe? I was looking at http://www.microflight.com/Online-Ca...dapter-Set-4mm, but I dont like idea of paying 16$ for a tiny piece of plastic.
dz,

Are you in the U.S.?

http://www.radicalrc.com/category/Pr...-Etc.-36/rec/0

http://www.micronradiocontrol.co.uk/prop_adapter.html



rc
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Old Jun 01, 2011, 04:44 PM
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Sealing gaps

Ok, so I've been reading this model aerodynamics book, and for reducing drag it said to seal up the control surfaces or gaps in the wing. So I looked at my ultra micros and saw that the tail had seams and the wing also had seams too. Those cause some amount of drag (says the book). Would it be wise to seal the gaps with tape? Would it be worth the weight of the tape?
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Old Jun 01, 2011, 07:53 PM
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Hmm...
Sealing the seams with tape seems to put too much stress on the servo. Any other materials that can be used?

Will sealing hinges at this scale matter? The umx beast and Sbach have sealed tail control surfaces, so maybe....
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Old Jun 01, 2011, 08:15 PM
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Originally Posted by Cheese5 View Post
Ok, so I've been reading this model aerodynamics book, and for reducing drag it said to seal up the control surfaces or gaps in the wing. So I looked at my ultra micros and saw that the tail had seams and the wing also had seams too. Those cause some amount of drag (says the book). Would it be wise to seal the gaps with tape? Would it be worth the weight of the tape?
Cheese,

On larger models, gapless control surfaces dramatically increase control authority, and they are absolutely mandatory on high-speed planes to prevent flutter. There are two concerns regarding adding gap seals to such a small model as the XP. The weight penalty at this scale (as you noted), and servo loading. My gut tells me that it wouldn't be worth it on something like the XP. The ailerons are essentially gapless already, and the gap on the tail surfaces is quite narrow. The drag is already so high due to the crappy Reynolds number at this scale - I doubt that it would be worth it in terms of drag reduction. However, it may improve rudder & elevator authority a bit.

That said - you'd need a gap seal that was about as flexible & light as Saran Wrap at this scale to minimize servo loading & weight.

Joel
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Old Jun 01, 2011, 09:25 PM
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Originally Posted by turboparker View Post
Cheese,

On larger models, gapless control surfaces dramatically increase control authority, and they are absolutely mandatory on high-speed planes to prevent flutter. There are two concerns regarding adding gap seals to such a small model as the XP. The weight penalty at this scale (as you noted), and servo loading. My gut tells me that it wouldn't be worth it on something like the XP. The ailerons are essentially gapless already, and the gap on the tail surfaces is quite narrow. The drag is already so high due to the crappy Reynolds number at this scale - I doubt that it would be worth it in terms of drag reduction. However, it may improve rudder & elevator authority a bit.

That said - you'd need a gap seal that was about as flexible & light as Saran Wrap at this scale to minimize servo loading & weight.

Joel
Thanks for your input (always informative and helpful). I guess I'll leave the gaps for now. I'm trying to get my p51 micro to fly faster at a lower throttle level. I can remove weight, lessen drag or increase the ESC + battery. For #1 I've removed every little piece of glue not needed and weakened the whole structure down. For #2 I'm working on that, may need to sand down a bit more. For #3, I don't think it is worth the money to get more power for the mustang by trading off slow speed flight for speed.

Is there any good way to put Saran Wrap on the hinges?
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Old Jun 01, 2011, 10:21 PM
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Originally Posted by Cheese5 View Post
Thanks for your input (always informative and helpful). I guess I'll leave the gaps for now. I'm trying to get my p51 micro to fly faster at a lower throttle level. I can remove weight, lessen drag or increase the ESC + battery. For #1 I've removed every little piece of glue not needed and weakened the whole structure down. For #2 I'm working on that, may need to sand down a bit more. For #3, I don't think it is worth the money to get more power for the mustang by trading off slow speed flight for speed.

Is there any good way to put Saran Wrap on the hinges?
Cheese,

Thanks! Glad I could be of help.

Not sure. Maybe use a very thin film of Zap Goo? It works great on foam. Not sure if it will stick to Saran Wrap, though. Maybe some thin foam-safe ca? Again, I'm not sure if it will stick to Saran Wrap. If you're good with really small stuff, maybe you could cut a strip of SR, and then use two thin strips of blenderm tape to hold it down.

Again - I doubt that it will increase the speed of your UM P-51 enough to notice, as there are other factors that dominate the total drag at this scale. Even if it did help, it would most likely be something like 1-2 MPH. Hardly worth the effort. If you really want to increase the speed without sacrificing slow-flight - put a Bravo SX motor in it, throw on a 5043, and slap in a Hyp 180 or 240. That will provide a significant bump in speed - with no effect on slow-flight.

Joel
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Old Jun 01, 2011, 10:32 PM
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Originally Posted by turboparker View Post
Cheese,

Thanks! Glad I could be of help.

Not sure. Maybe use a very thin film of Zap Goo? It works great on foam. Not sure if it will stick to Saran Wrap, though. Maybe some thin foam-safe ca? Again, I'm not sure if it will stick to Saran Wrap. If you're good with really small stuff, maybe you could cut a strip of SR, and then use two thin strips of blenderm tape to hold it down.

Again - I doubt that it will increase the speed of your UM P-51 enough to notice, as there are other factors that dominate the total drag at this scale. Even if it did help, it would most likely be something like 1-2 MPH. Hardly worth the effort. If you really want to increase the speed without sacrificing slow-flight - put a Bravo SX motor in it, throw on a 5043, and slap in a Hyp 180 or 240. That will provide a significant bump in speed - with no effect on slow-flight.

Joel
In my micro mustang, I have a 1S brushless AP05, XP-3A, hyperion 180mah and 240mah batteries, and 5043 prop combination. I dropped the brushed motor, I like the quiet whine of the brushless. I'll try the wrap and tape idea on my sukhoi xp first. If it works (1 or 2mph increase is nice) then on to the micro mustang.
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Old Jun 01, 2011, 10:55 PM
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Originally Posted by Cheese5 View Post
In my micro mustang, I have a 1S brushless AP05, XP-3A, hyperion 180mah and 240mah batteries, and 5043 prop combination. I dropped the brushed motor, I like the quiet whine of the brushless. I'll try the wrap and tape idea on my sukhoi xp first. If it works (1 or 2mph increase is nice) then on to the micro mustang.
Ahhh...I wasn't aware that you're running a bl setup in the 'Stang. Is it faster than an XP w/5043 & a Hyp cell? If so, it would be a good idea to use gap seals as 'flutter insurance' - even if they don't measurably increase speed.

Joel
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Old Jun 02, 2011, 08:02 AM
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thanks a lot, ordered from radicalrc. may be such info we could add in first post or smth?
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Old Jun 02, 2011, 09:08 AM
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thanks a lot, ordered from radicalrc. may be such info we could add in first post or smth?
Just FYI... if you ordered more than one then they will all come in a bundle and still attached to the main piece of wood that they were created from. You will need to cut them loose. I found this to be a little bit of a pain in the arse. As a backup I just bit the bullet and also ordered the plastic adpaters from Canada... but it really DOES suck to pay $16 shipping and wait for a week and a half to get a $3 part.
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Old Jun 02, 2011, 06:24 PM
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Originally Posted by turboparker View Post
Ahhh...I wasn't aware that you're running a bl setup in the 'Stang. Is it faster than an XP w/5043 & a Hyp cell? If so, it would be a good idea to use gap seals as 'flutter insurance' - even if they don't measurably increase speed.

Joel
Nope its not as fast as the sukhoi xp with the 5043/ hyperion cell. It seems slower in comparision with stock. Since the setup added 2g to the mustang with was already at 43 AUW. So even though the bl motor generated more power ( a few grams of thrust over stock motor that I had) it wasn't enough to pull the mustang faster. The thrust to weight ratio is at 1:1 for a few seconds then it drops down. The sukhoi xp wiht the 1S bl setup feels faster since it was already lighter and the old brushed motor was going out. I'm going to try attaching the wrap on and see if it stays. If the wrap is wrinkly when attached it might cause more drag than without. So smoothing it would be a challenge. We'll see...
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