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Wot 4 tail heavy

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Mike Pendleton24/03/2015 18:17:46
8 forum posts

I've just finished a Wot 4 Classic which has come out at 80oz with an OS46LA. It is tail heavy with the battery (4 cells 2 on top of 2) against F1. It needs about 4oz of lead on the nose to balance. I am thinking of lightening the tail by cutting holes in the horizontal and vertical surfaces. Can anyone give advice on how big these can safely be please?

Keith Evans 324/03/2015 18:44:21
372 forum posts
81 photos

If you think about it a , lot of planes have flown quite successfully with built up tail surfaces .I would suggest various hole sizes the largest being closest to the fuselage and leaving about three eights of an inch between them and the surrounding outlines .

Depending on the wood density it may or may not make a great deal of difference to the position of the balance point .

Best of luck

cymaz24/03/2015 18:53:44
8772 forum posts
1190 photos

A club friend of mine has a Mk1 Wot4. He needed about 4oz on the nose. Its powered by an OS 46la. Flies well.

Add the lead, see how it flies. It will be an easy fix, slightly more than cutting holes. If you don't like it then carry on with the carpentry!

The stated balance point in the book is spot on for good flying

Delta Foxtrot24/03/2015 19:45:24
566 forum posts
91 photos

I would not advise lightening the tail surface by cutting holes in it. I think the weight saving will be small and you will reduce the strength of these surfaces. If you want a lighter tail then a properly built up tail using the correct grain direction on each member would be strong and light.

I would try flying it properly balanced as is with nose weight to achieve the CG position. You could then try removing some bit by bit to see if you can get away with less.

Happy flying


iqon24/03/2015 19:51:44
1466 forum posts
239 photos

If it`s covered , why would you want to put holes in, I would add the 4oz and fly it , you might end up taking the weight off again, also is there room for a 6v battery...

Biggles' Elder Brother - Moderator24/03/2015 19:52:59
15748 forum posts
1460 photos

4oz of lead really isn't that much - the model has a big wing and can easily carry that without significant loss of performance. I'd go for that.


fly boy324/03/2015 20:05:55
3532 forum posts
18 photos

A club member did a lot of so called "lightening holes" during a build. Took a lot of time and effort to get things correct, using different copper tubes for various diameter holes. He weighed the removed balsa discs, and found there was neglegible weight loss. A total waste of time. Cheers

Mike Pendleton24/03/2015 22:54:43
8 forum posts

Many thanks to you all. I was particularly interested in the helpful comments on flying with the extra weight, and on the results of cutting holes. Very much appreciated.

Rosco24/03/2015 23:39:56
448 forum posts
386 photos
Hi mike,
Remember that the further out the weight ie at the very ends of the fuselage, the less you will need therefore sometimes I have corrected COG issues, particularly tail heaviness by just adding a slightly heavier spinner.

I don't have a Wot nor any engine powered models but this might help if you wish to add useful weight as opposed to dead weight.

onetenor25/03/2015 04:18:48
1900 forum posts

Using a 6 v battery would add weight anyway so overall weight would wnd up the same

..25/03/2015 07:12:51
974 forum posts
1 photos

Shoehorning a 6v pack under the already crampt cowl isn't going to help performance so just add the wieght & see how it flys.

Even the ARTF version needs a fair chunk of lead with that size of engine.

GrahamC25/03/2015 08:18:20
1234 forum posts
196 photos

Like others, I'd start by adding the weight and see how it flies. I had a wot 4 ARTF for a long time and had the cofg some way back from the recommended point. Seems to me that it's pretty common for the recommended point to be on the conservative side, and many models are significantly improved by a more rearwards CofG.

I started with a block of lead on the engine mount, and ended up with a weight on the tall of the aforesaid artf model (partly because IC ouldnt be bothered to dig the fuel tank out and move the battery back!

Also to a point, weight is not that much of a problem with a wot4 - it will be your friend when the wind picks up

Richard Wood25/03/2015 08:28:43
1094 forum posts
164 photos

Hi Mike,
One thing you can also try is moving the engine further out on the mount a little if
there is space on the bearers to do so.
I did this on one model with reasonable success & no problems with engine security
or increased vibration.
Alternatively you could fix the engine mount to a ply plate secured to the bulkhead to
shift weight forward a tad.
As said though, a little extra weight will not harm a Wot4.

RC Plane Flyer25/03/2015 08:51:06
655 forum posts
19 photos

Hi Mike Have you got the battery mounted in the tank bay? or even fixed to the motor mount. I have had to do this in my ARTF Acro Wot . I have seen people move the servo bay forward on ply plate so that can it be removed if access to tank is needed

Ian Jones26/03/2015 00:51:10
3218 forum posts
1397 photos

The LA is a lightweight engine anyway, probably lighter than the WOT4 was originally expected to carry and I suspect that is why it's come out light at the front as opposed to tail heavy, if you see what I mean.

In which case sticking some extra weight on the front as others have suggested would just be compensating for a light front end and at 84 ounces would be within the design weight.

Edited By Ian Jones on 26/03/2015 00:53:16

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