UMX Carbon Cub SS Mod Thread - Page 31 - RC Groups
 Nov 28, 2012, 12:26 PM Registered User Beware of footprints in the snow. I hear they are not good. MIke
 Nov 28, 2012, 03:23 PM Registered User [QUOTE=ChinoDiablo;23381081]Joel, While the ratio of 1/17 scale applies to inches and feet, does it apply to weight? Is the UMX CC 1/17th the weight of the real thing? It would seem to me that efficacy on snow for skies for a CC is more a function of weight and area than of just area. Not trying to be argumentative, just trying to understand scale. QUOTE] Scaling isn't 1:1 for model flight. If I recall correctly weight is 1/x^3 different. Meaning if the length of the aircraft was 1/2 then scale weight is 1/8th. Speed is x^(.5). So if a aircraft is half the length it can be expected to have 70% of the speed To learn more try to google dynamic scaling though doing that real quickly got me bad results. The main thrust of it is that you can expect models to be relatively lighter and faster as you get smaller.
 Dec 03, 2012, 01:37 AM Registered User Hi, I want to replace my Cub's wheels with ones of a greater diameter - Here comes dumb question of the day... How do the wheel retainers come off? I don't want to break anything trying to remove them in the wrong manner!
Dec 03, 2012, 06:48 AM
Registered User
Quote:
 Originally Posted by kimheath Hi, I want to replace my Cub's wheels with ones of a greater diameter - Here comes dumb question of the day... How do the wheel retainers come off? I don't want to break anything trying to remove them in the wrong manner!
They're just pressed on so just pop them off. If they become a little loose, a tiny drop of CA on the tip of the wire will keep it on.
Dec 03, 2012, 04:54 PM
Registered User

# Hi everybody

I like the Carbon cub, but during the last flight suddenly grew up the pole from the soccer gate. I hit this hardly and cub spinning to the ground . The left wing ripped of. I used the UHU por, and looks good now and also I added the pilot for next time to have second pair of eyes to watch obstacles. It is not painted yet.

Watch out pilots!

### Images

Dec 04, 2012, 12:54 AM
Registered User
Quote:
 Originally Posted by kimheath Hi, I want to replace my Cub's wheels with ones of a greater diameter - Here comes dumb question of the day... How do the wheel retainers come off? I don't want to break anything trying to remove them in the wrong manner!
The wheel wire ends are threaded so you can also twist them off and then find somthing to twist back on. Servo arms cut down work as the holes are the same size. .047. Dubro makes hubs that screw on nicely. Shrink tubing in a couple of layers holds the wheels on and looks good.
Mike
Dec 04, 2012, 09:30 AM
Registered User
Quote:
 Originally Posted by shastamike The wheel wire ends are threaded so you can also twist them off and then find somthing to twist back on. Servo arms cut down work as the holes are the same size. .047. Dubro makes hubs that screw on nicely. Shrink tubing in a couple of layers holds the wheels on and looks good. Mike
Would this approach work for 1.75" Dubro wheels (175SL)?
Dec 04, 2012, 11:45 AM
Registered User
Quote:
 Originally Posted by lmcwilli Would this approach work for 1.75" Dubro wheels (175SL)?
The 175SL has a 1/8in hole .125. The CC wheel wire, axle is .047. I put the 1.25 Dubro tires on my CC, can't find the site, sorry. You are going to have to do some scouting on the Internet. Some sites list the axle size of the holes and some don't. Others here have mounted the tires you mentioned and would be able to help.
Mike
 Dec 04, 2012, 12:11 PM Make the best of all you have Bought some 45mm wheels, sanded the original so that they were 4 mm wider than the hole in the 45mm tire and pressed them in, ready for take off - on grass ! Even towing my fathers ASK from grass is no problem ... Rolf Last edited by beetyii; Dec 04, 2012 at 12:43 PM.
 Dec 04, 2012, 12:31 PM I'd rather be flying! Now, there's a set of Alaskan Bushwheels - UMX-style! Very nice! Joel
Dec 04, 2012, 01:50 PM
Registered User

# Flaps on the UMX Carbon Cub

I just took my new CC out and tried the flaps on takeoff and after powering up, it went almost straight up.I thought I put in 40% in the radio, but do I need to mix in elevator trim when using flaps? Didn't crash, but was a little harry! I was using my DX6i, but I also have a DX7 if it makes any diff. Thx.
Dec 04, 2012, 02:29 PM
I'd rather be flying!
Quote:
 Originally Posted by georgegv I just took my new CC out and tried the flaps on takeoff and after powering up, it went almost straight up.I thought I put in 40% in the radio, but do I need to mix in elevator trim when using flaps? Didn't crash, but was a little harry! I was using my DX6i, but I also have a DX7 if it makes any diff. Thx.
First off, only 10-15 degrees of flaps are used on takeoff - if they are used at all. Anything more than that will actually hurt takeoff performance, due to the large amount of drag. 40% is way too much on takeoff. Secondly, flaps are designed to be used only at low airspeed. If you use them on takeoff & during the climbout, you need to carefully manage your airspeed. If the plane is climbing wildly with the flaps extended, you're using too much flap, flying too fast, or a combination thereof. As it says in the manual, retract the flaps before adding power.

It's best to either assign the flaps to a proportional control or set up multi-position switched flaps. I fly with a Futaba 10CHP so I'm not all that familiar with Spektrum rigs, but I'd think that you should be able to set up proportional or 4-position flaps on your DX7 - depending upon which model of DX7 you have.

From my Carbon Cub handling checklist:

To improve handling when flying & landing with flaps:

• If this is your first flap-equipped plane, get used to how it handles clean before experimenting with the flaps. If this is your first or second aileron plane, you will most likely find the plane to be a handful when slow-flying with the flaps even partially extended. Make sure you are flying at least 3 mistakes high until you get used to how the plane behaves when there is little air flowing over the control surfaces. If you think you're about to lose control - retract the flaps, smoothly go to full-power, and get the nose down. Keep the nose down until the plane is flying again.
• Make sure the plane is not tail-heavy. With the CC, even a slightly-aft CG will result in mushy handling when flying circuits with partial flaps.
• Do not fly around with the flaps fully extended. Full-flaps are for steep approaches - not slow-flying. If you are stuck with one flap setting, reduce the throw to 50% or less if you want to fly slow circuits with the flaps down. If you are serious about the hobby & think you may want to try more full-featured planes in the future, consider upgrading your tx.
• If your tx allows, set up at least two flap positions (half & full). Three or four positions would be better. If your tx has flap delay - use it! Alternatively, assign the flaps to a conveniently-located proportional knob or slider, if one is available. Preferably, one with a center detent position that you can use for slow-flight. The CC uses channel 5 for flaps, which is typically the gear channel on the tx. If you're flying with a DX6i, see the following post for a way to mix the gear channel to the flap channel & have 3-position flaps: https://www.rcgroups.com/forums/show...postcount=1841
• If you find managing the airspeed, throttle, elevator, and flaps all at once to be overwhelming, try the flap-elevator mix. But don't make the mix so aggressive that you can drop the flaps at cruise speed without ballooning. As you get more comfortable with the workload, slowly reduce the mix. You may find that you don't need it anymore. Those who would like to add a little taste of full-scale flying to their RC flying may even find that they enjoy 'feeling the plane' - as one pilot put it.
• Reduce power & wait for the nose to drop slightly before extending the flaps.
• Manage the throttle carefully when flying with the flaps extended. Be sure to retract the flaps before adding power - as stated in the manual. For instance - if you're doing a slow flyby with partial flaps, retract them before adding power after the pass. If you're on approach with partial or full-flaps and need to abort the landing - immediately retract the flaps, advance the throttle, wait for the plane to gain speed, and then ease the stick back. The plane will most likely lose some altitude as you retract the flaps, but resist the temptation to abruptly haul the stick back. Wait for the plane to gain speed, then smoothly pull up & make your go-around.
• Be smooth & deliberate on the sticks (including throttle) when slow-flying with partial flaps. Remember that control authority will be significantly reduced, due to the lower airspeed. The reduction in control-authority becomes more pronounced as the flaps are extended further & the plane slows down. Avoid steep bank-angles when flying with the flaps extended. Make gentle, coordinated turns. Initiate the turn with rudder & maintain bank-angle with ailerons. Don't let it get too slow. Do not abruptly increase the throttle, as this may cause an abrupt pitch-up, followed by a stall. At low altitudes, this often results in a crash. If you find yourself in this situation, immediately retract the flaps, smoothly go to full-power, and push the nose down to build airspeed & get the plane flying again.
• Avoid flying & landing in gusty and/or turbulent conditions with the flaps extended.
• Avoid crosswind landings with the flaps extended.
• When landing with flaps in anything more than a very light breeze, retract them immediately after touchdown to help keep the plane planted on the runway.

Here's an example of how she can fly when set up & flown as described in my CC handling checklist. I am flying with the GWS 5030 prop & a TP 325 mAh 65c 'UMX' pack:

 Having some fun in the yard with the UMX Carbon Cub. (6 min 32 sec)

Joel
Dec 04, 2012, 04:32 PM
แอนครู กรีน (เขียว)
In post #428 point #4 Turboparker mentioned calibrating the ESC...
Quote:
 Originally Posted by turboparker Gator, As Microheli noted - a CC with the 2300Kv motor, 5030, and a Hyp 240 pack should have no trouble hanging on the prop. Here's a checklist: Verify that the motor isn't rubbing on something. Make sure that the prop isn't slipping. Verify that your throttle travel is set to 100% & that you don't have low rates, throttle-cut, or any throttle mixes accidentally programmed. Calibrate the ESC. Verify the integrity of the motor wiring, power wiring, and the connectors. If you've done all of the above & the problem still exists, it is either the motor or the brick. Joel
In the instructions it mentions getting into ESC programming mode but not how to do anything with it. Are there any instructions for properly calibrating it? I ask as I'm flying my CC on a Futaba 8FG with an external Spektrum module as posted here by IvanC and I don't really know if the travels are exactly the same as a native Spektrum Tx, I'm guessing it's about right as the throttle feels reasonably linear and she'll prop hang in the early part of a flight. Currently down as I have yet to fit my replacement prop driver (one nose over too many!) I'm running Mosquito mainwheels but I think I need something a bit little bit bigger, but I'm wary of the weight as it seems to me to be nose heavy already.

Andrew

Forgot to mention, I was in my LHS (Oxford, UK) at the weekend and they've just had a new delivery of CC's and the one I looked at didn't have the ventilated windscreen and servo covers??? It was still in the box so I couldn't see the motor or rear under fuz area....
Last edited by C Andrew Green; Dec 04, 2012 at 04:35 PM. Reason: Added a bit
Dec 04, 2012, 04:45 PM
Registered User
Quote:
 Originally Posted by C Andrew Green Forgot to mention, I was in my LHS (Oxford, UK) at the weekend and they've just had a new delivery of CC's and the one I looked at didn't have the ventilated windscreen and servo covers??? It was still in the box so I couldn't see the motor or rear under fuz area....
If there is no vent hole in the windshield or servo covers I very much doubt, but couldn't prove that what you saw was the improved version. The model numbers are the same. Eflight just graciously and smartly (thank you) made improvements without calling attention or changing model names. I wonder if this is so they wouldn't ruin sales for LHS's having older models that wouldn't sell once the V2 word got out?
BTW the motor in the improved version is the same 2500kv, but really and nicely quiet.
Mike
 Dec 04, 2012, 05:08 PM แอนครู กรีน (เขียว) Hi Mike, It was definitely fresh stock from Horizon as most everyone in the UK has been out of stock for a while, mine was a little flown second hand example from the same LHS a couple of weeks earlier as no one had stock! That's why I was surprised not to see the vent holes.... mine is from the previous batch as far as I can tell, and has a 3200Kv motor. Andrew