Originally Posted by leethetreeguy

Mac, I am proud to say...Your "dime mod" fixed my UM Corsair. Thanks buddy. I flew some really nice circuits. Did a loop or two and a victory roll. Woot. Three cheers for Mac..."hara, hara, hara" aahahahaha. You da man. Lee

Yup, my own formerly unruly UM Corsair is now stepping-and-fetching, with the addition of a dime under the cowl. It previously seemed so 'roll-happy' that it was hard to get it in sustained straight and level flight, and it also was difficult to fly it while slowed down and 'parading' around the field like my trusty UM T-28 can do. After doing adding the dime with some two sided tape and brushing it with my white paint-stick to blend with the fuse, today I was able to fly it slow, and also still do all the rolls and loops it used to do, but now I could also slow it down and finally even use the rudder to command some slow turns without having to 'yank and bank it' with ailerons. Using more rudder to turn lets it preserve altitude, for as you guys who fly it know, whenever you turn it with elevator and ailerons, it loses a lot of altitude, so you then have to leave the elevator in to get it reestablished in level flight.

In short, this has transformed my hanger queen into a member of the active fleet!

When describing my set-up, I forgot to mention I took the LG back off it. Lee

Originally Posted by airpower

I know all the 4 channel brushed ums use the same motor, but i didnt wanta start a new thread. I have alot of.experience with these things, but every once in a while the gearbox turns roughly, smoothly, but with alot of resistance. I didnt care on my old sukhois, but when it happenned after 4 flights with my brand new corsair, i neededto figure it out. The prop shaft it not screwed on too tight, i lubed it, no foam is stuck in the gearbox, anyone solved this?

I am not sure what you mean by "every once in a while". Does it do it sometimes but not other times, or does it just start doing it at some point and then keep doing it? So far it seems like I got lucky with the motor in the Corsair, but I am on the 3rd one with the Mustang and it is not sounding great.

The Corsair is such a sweet little plane that it would probably be worth the effort of putting a brushless motor in. More power, longer lasting, and it would probably solve the tail-heavy issue as well. I have also noticed that the stock motor is the same size as the one in the MSR and also the tail motor in the 120 SR. Those 2 motors seem to go on forever. Might be worth trying one of them instead of the iffy UM motors.

The mSR uses the same motor as the XP/F4U,Pole Cat, etc., but with a different pinion. Therefore, it will not last any longer in the F4U. It's the application that determines the longevity of these cheap 'pager motors'. We have seen up to 20% variability in thrust between samples, and longevity is all over the map. Some motors last for hundreds of flights, while others fail before the plane even gets airborne for the first time. Most fall somewhere between. Remember, the manufacturer never intended these motors to be used as powerplants. Rather, they were designed for low-stress, intermittent use - such as vibrating pagers & cellphones, and operating optical disc drawers, carousels, and the like.

The Nine Eagles Solo Pro motor is currently the best option for a longer-lasting, direct-fit brushed motor with similar power to the stock setup. It has the same power as one of the stronger F4U motors. The Nine Eagles Bravo XP motor provides a 30% increase in thrust over the stock motor when both are running 5043 props & top-quality batteries, and also tends to outlast the orginals. Of course, top-quality batteries are mandatory with this setup.

The Nine Eagles motors have the same external dimensions as the original, so it's an easy swap. Just put the PZ pinion on the new motor, swap the motor connector, and you're all set.

See the SP/SX motor swap thread for details: http://www.rcgroups.com/forums/showthread.php?t=1326158

Joel

Thanks for the info. Now that I look closer, I can see that the pinion on the UM motor has 9 teeth and the one on the MSR has 8. Of course, it is also driving a larger secondary gear. I was just hoping since one was PZ and the other was Blade, there might be a difference in where they sourced their motors.

Hey, Joel, I was just wondering... instead of the extra weight of an esc and a 2s battery and a brushless motor, what if you used a larger brushed motor, like the one in the MCPx? Do you think the esc on the board could handle that (or some other slightly larger motor)?

If I remember correctlly, the ESC will only put out like 3.5amps and will only run on 4v or less. Lee

Originally Posted by Jovanx

Hey, Joel, I was just wondering... instead of the extra weight of an esc and a 2s battery and a brushless motor, what if you used a larger brushed motor, like the one in the MCPx? Do you think the esc on the board could handle that (or some other slightly larger motor)?

The mCP X motor won't fit the gearbox at all. As Lee noted - you may also run into the ESC's limit. If you want a more-powerful brushed motor, just use the Bravo SX motor. It fits the gearbox without mods & generates 30% more thrust than a strong stock motor. Plus - it's already been tested, and the ESC can handle it just fine. Swap the pinion & connector - and be sure to use a top-quality 1s battery. RCBabbel's testing showed a whopping 60 grams of thrust with that motor on a 5043 & Hyp 240 cell. Contrast that to 40+ grams of thrust with the same prop & battery on the stock motor. With the SX motor/5043/top-quality battery, your F4U will have essentially unlimited vertical performance. The thrust-to-weight will be similar to that of the UMX Beast.

If you're not comfortable with doing the pinion & connector swap, RCBabbel sells plug & play Bravo SX motors & SP motors.

Joel

If I thought that MCPx motor would work, I would make it fit somehow. Anyways, I am going to take your advice. I just contacted RCBabbel to see what he has in stock.

Put the guts from a beast in a corsair but nocked the antenna off the board so it has not been flown yet ,so now I have to take it apart again hope the piece of wire iv selected will work .

Jovanx, i noticed that after flying the prop on my corsair was tough to turn, and also the left prop on my my mosquito. But a couple hours after flying the prop spun as freely as they were new. So apparently its a cooling issue?

Hey guys, new to the thread but not new to the UM series or the hobby. Finally picked up the Corsair (and Mrs. Claus got me the full size for Xmas, which is still looking at me in the box crying to be let out!!!) & thought I'd take a peak at the forum. I've skimmed over some pages in the beginning & end. Looks like the "Dime Mod" works out well!! Any other mods/adjustments I may want to look into before her maiden flight. Looking to keep her stock as far as motor & props goes. Thanks in advance!! Coconut

Welcome Coconut. The dime mod may or maynot be neccesary. You have to check your planes COG (center of gravity). The stock prop? I can tell ya right up front, change it for the mustang prop. Save the stock one for looks on the shelf. It does not provide enough thrust. Happy Flyin. Lee

Regarding receive antenna replacement....

The most important things are that the replacement antenna wire is the same length & diameter as the original, and that it uses the same type of insulation. Antennas are typically tuned for resonance at the frequency of operation. Antenna length determines the resonant frequency. Shorter = higher frequency, while longer = lower frequency. The length-to-diameter ratio determines antenna bandwidth (range of frequencies over which the antenna will efficiently operate). Fatter = wider bandwidth, skinnier = narrower bandwidth. Length-to-diameter ratio also has a lesser effect on resonant frequency. A fatter antenna needs to be a bit shorter than a skinny antenna. The type of insulation (or lack thereof) also affects the resonant frequency. An insulated antenna needs to be a bit shorter than an antenna made from bare wire.

An improperly-tuned receive antenna will always perform far worse than a properly-tuned antenna. Incidentally - an improperly-tuned transmit antenna will not only perform poorly - it will usually destroy the transmitter's power amplifier. Never attempt to repair or modify a transmit antenna - unless you have an in-depth understanding of antenna theory & RF, and have access to proper RF test equipment that is designed to be used at the transmit frequency.

Joel

Originally Posted by leethetreeguy

Welcome Coconut. The dime mod may or maynot be neccesary. You have to check your planes COG (center of gravity). The stock prop? I can tell ya right up front, change it for the mustang prop. Save the stock one for looks on the shelf. It does not provide enough thrust. Happy Flyin. Lee

Thanks....... And that's what I forgot to ask, the prop. Don't even try the 3-bladed just go straight for the P51 prop huh. Will do and thanks again!! Hope to fly on Monday!!! You guys have a good weekend, Happy Landings!