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Aug 23, 2019, 04:51 PM
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New Timber UMX


Took delivery of my first plane today. a new E-Flite Timber UMX . Inspecting it Iím not sure if the motor and prop are square to the body. is this normal? What do you think? If it isnít is there any adjustments possible? Thanks.
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Aug 23, 2019, 05:45 PM
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balsa or carbon's Avatar
Yes , that's normal ..... it's called right thrust , and it compensates for motor torque wanting to roll the plane to the left .

If you look from the side , it may also have a little bit of down thrust . The down thrust compensates for a high lift wing wanting to balloon : the nose "floating up" .


I put a lot of right thrust and down thrust on this home made plane ↓


Lightweight 40" wingspan FT Old Fogey-ish (2 min 58 sec)
Last edited by balsa or carbon; Aug 23, 2019 at 05:54 PM.
Aug 24, 2019, 02:07 AM
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Phew, thought I was going to have to send it back.

Thanks for the info. Your plane is very graceful, what a great slow flyer.
Aug 24, 2019, 01:07 PM
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balsa or carbon's Avatar
Quote:
Originally Posted by KPB.in.UK
Phew, thought I was going to have to send it back.

Thanks for the info. Your plane is very graceful, what a great slow flyer.
Enjoy your new Timber UMX !

If you are interested in building home made planes , let me know .... I'll be glad to help . It can be very rewarding to fly a plane you've built yourself ! And if a home made airframe is crashed beyond repair , you simply make another one .
Aug 26, 2019, 10:12 AM
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First flight.


I spent yesterday, getting the Timber ready for first flight, glued on the slats and completed programming the radio. Tested controls and all was well. Tested the CG, with the battery all the way forward it still seemed a bit flat. Iím new to planes so wasnít entirely sure how it should sit. There was a good opportunity today with no wind ( one less thing to worry about) to give it a try. Took it to my village football (soccer) pitch to try. I found the grass too long for a ground takeoff, so thought I could hand launching it in SAFE with takeoff flaps. Yes it worked and flew nicely ( if you can all SAFE mode flying). I did a few laps of the field still with takeoff flaps and then tried turning SAFE off to see if I could trim it. Immediately it went nose up and I turned SAFE back on. Something is not right. Did a couple more circuits and managed to land safely.

My first thoughts were Iíd seen a youtube where someone added some down elevator to the flaps which Iíve done. But Iím wondering what effect this will have on Safe mode? Will it be seen as a down elevator input and cause it to fly down next time I hand launch?

Next Iíve revisited the CG and tried to get a little nose heavy. Even with the battery all the way forward Iím not convinced it is balanced. But initially thought the manufacturer must have tried this. Anyway, I did a few tests adding weight and ended up with 5g (0.18oz) of lead attached to the back of the motor mount with blu-tack. With the extra weight the nose is further down than it was, but not much, but got worried about adding any more. And the battery is still all the way forward to the lead and motor mount. Not ideal if it goes in nose first at any time.

Should I take out the flap elevator mixing I added after my first flight?

Is my weight modification ok?

Am I right in thinking I canít trim the plane with flaps out in Non Safe Mode it needs trimming with flaps up?
Aug 26, 2019, 11:45 AM
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balsa or carbon's Avatar
Did you center the control surfaces as instructed in the manual ? And then fine tune the trims in flight ( SAFE OFF ) ? See screenshot from manual below . Inflight trimming should be done with the flaps up ( normal flight ) .

When putting the flaps down , you can compensate for the ballooning ( nose "floating up" ) manually ( down elevator on TX stick ) or with a mix ..... either way works .

If the CG at 28mm balances the plane level , you're good to go .
Aug 26, 2019, 12:01 PM
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balsa or carbon's Avatar
When the SAFE is on , the SAFE moves the control surfaces to keep the plane level .... whether the flaps are down or not . I would test the flap/elevator mix by hand launching the plane with SAFE ON and flaps up , then put the flaps down while the plane is in the air at a comfortable altitude ( 2 or 3 mistakes high ) .

And remember that you only need as much throttle as is necessary to keep the plane flying ( above the stall speed ) . Beginners often launch at full throttle , and then fly the entire flight at full throttle . That is not necessary , and makes flying more difficult .
Aug 27, 2019, 02:36 AM
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Thanks for the info.

I did check all control surfaces, which all looked good, apart from a small centring error on the rudder, which needed an opposite flick to return to center from one direction. After the flight I made a small adjustment so that it was the same in both directions.

Iíll recheck the C of G again.

The ballooning caught my by surprise I didnít expect it to do that. Iíll be more prepared next time. The football pitch is only 100 by 50 yards with large trees around on three sides. I was flying as slow as I dared with landing flaps and it still covered that distance quickly. Looks like I need to find somewhere larger to test it and get it trimmed.

Another great flying day today with no wind, typical. I had months of windy gusty days, then as soon as the aeroplane arrived calm conditions and Iím not ready. Oh well back to helicopter hover practice.
Aug 28, 2019, 05:28 AM
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Being a newbie, I found it a bit difficult to hold the plane and check from the side so made a support out wood scraps. I have have checked the CG again. First photo shows it with the lead attached to the motor mount and battery all the way forward. It still looks a little tail heavy to me. So Iív cut the lead in half and put it right up the front behind the LEDS as shown int the second picture. The third picture shows it again with lead up the front and the battery all the way forward. And I think it finally looks balanced.

Hopefully Iím good to go now. Just need to find a better location, and wait for the weather.

Thanks for the help.
Aug 28, 2019, 08:26 PM
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FoxProGT's Avatar
If you turned off SAFE while the flaps were down, even if the plane is a little nose heavy it'll pitch upward.
Its normal for most planes to pitch upward when the flaps are dropped.
Adding down elevator mix is an option to keep it level.
You should practice flying the plane without flaps until you get a good handle of its characteristics.
While flying without SAFE, get it to fly nice and level before you start playing with flaps.
Just a suggestion.
Good luck.
Aug 29, 2019, 03:42 PM
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dalecheek1's Avatar
This plane does not need any nose weight period.So take it out of the plane.
Aug 30, 2019, 03:17 AM
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I have an Eflite Maule (very similar to a Timber) and I never use the flaps, this plane has such great flying characteristics I find the "up ballooning" when flaps are deployed a nuisance. I did not use the leading edge slats. I fly it with both a 2200mAh and a 3200 mAh battery which have a significant difference in weight and do not find it necessary to rebalance when switching batteries. It balanced right out of the box with no lead.
Sep 03, 2019, 08:35 PM
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I add velcro further forward for the battery. I have it ouching the black plastic piece. Better cg. 2C 280 mAh. My friends who have done this agree it's a much better flyer battery forward.
Sep 04, 2019, 02:28 AM
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The picture is with the battery all the way forward to the motor mount + 5g in the nose. Only then will it balance at the right CG.

I couldn’t get velcro to stick to the plane that far forward, as its not flat and so the battery is not very secure. Maybe I can get a longer bit in, I’ll have another go.

The weather has changed here, back to wind and today rain too, so no chance to test again. The weather forecast isn’t good with wind every day for at leat a week.
Sep 04, 2019, 09:04 AM
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dalecheek1's Avatar
STILL does not need any nose weight period. My batt. is in middle of trey AND fly's neutral after doing the inverted flight test.


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