G.Barber

My Feedback: (1)

Just a little background here. Over the winter, I will be building and kitbashing a tower trainer 40. I plan to make it a taildragger, add flaps and use ailerons that are bigger. I also plan to set it up on my 7Cap so the flaps can be used as ailerons when not deployed as flaps.

My question is this: Can I use an os 61 fx on this size plane using a prop like a 13x4 as long as the plane balances on cg?

mpw_8679

Yes u can, just make sure your prop to ground clearance is ok.

G.Barber

My Feedback: (1)

I had planned on replacing the stock wire gear anyway, so I will get an aftermarket set, or solder up a new wire set toget ground clearance. I also had though about some "tundra tires". Am I looking at too much drag?

flyinrog

My Feedback: (1)

If you end up needing to add weight to the rear, try moving the battery back instead of actually adding weight, may have to go in and build a small shelf to put it on, but its still better than adding weight/lead to the plane....Rog

bingo field

If you are worried about tire sizes, don't. 3.75 - 4" tires will work fine, you will have more on your plate to concern yourself with for the first few flights than the little bit of extra drag. You will be so well overpowered it won't make a bit of difference. The larger tires will help in taxiing. Remember , if the mains get 4" tires, the nose wheel should be 3.75. I wouldn't go any smaller than that. Good luck!

Alex7403

if you are talking about the ARF:

Tower trainer 40 ARF with 61 FX not a good idea.

i'm not sure the tower trainer 40 ARF engine mount would accept the 61 FX!!!!
and the fire wall is designed for that mount only!!!

why not to take the 60 size trainer with that motor or the hobbico hobby star 60?

tower trainer is a very good airplane! (had two of them) one still flying.

more significant change would be replace the nose gear at least, no all the landing gear, the main and the nose and to recover it!

if you build it from kit then it will accept other engine mount, then you can put there the 61 FX.

besides that Tower trainer 40 fly's very well with 46 AX, mine flew really well with 46 LA.

Alex

Lnewqban

gabarber:

I had a 40 trainer with a 60 engine that did not live long.

More weight at front = more weight at the tail = heavier model = faster flight and landing / more inertia during maneuvers / harder crashes / higher fuel consumption.

What for? A little more of speed?

Trainers are designed for having high drag and strong decalage, which do not match with high speeds.

I am repairing the thing to be propelled by a 40 again.

More power is good for 3-D or for higher speed; I believe it is better used on a suitable model.

Regards!

Jetdesign

My Feedback: (8)

Do you already have the engine? The OS 55AX is made to be stuffed in .40 size planes. You get almost the same power as the .61, but size and weight closer to a .46. Great engines!

downunder

Below is my son's beaten up and many times repaired 40 trainer which now sports a 1.08 engine with the nose shortened by about 3" to help keep the CG correct. AUW increased from 5 1/2 pounds to 6 pounds which gave an unnoticeable increase in stall speed and the 14x6 prop combined with the much lower revs of the 1.08 kept the maximum speed virtually the same as with the smaller engine so aerodynamic loads in manoeuvres are also similar. In short, it's a blast to fly and wayyyyy better than with the original engine .

opjose

Actually it works just fine.

The FX is not as powerful as a .55 AX so there is little additional stress on the plane.

It fits and mounts w/o problems.

Jetdesign

My Feedback: (8)

Downunder, the is ONE UGLY PLANE!!! You must have such fun flying it!

saucerguy

I put a .40 equivelant brushless motor set up on a foamie that weighed 20 oz, it had a 14" prop to boot lmao. It tended to break props upon landing since you could only belly land the thing and it always came in hard, but what a blast to fly. Overkilling your power system in meager levels such as what you are doing merely means they will be a bit heavier and you have to mess with the COG a bit, in my case, the motor weighed a lot more then the rest of the plane itself, so just kind of flew it like a rocket, needless to say, the winds no matter how insane they were, were never an issue at all, it didn't even flinch at them.

Alex7403

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In the picture:
Tower trainer 40 ARF engine mount: ~35.4 mm
Width of OS 61 FX for mount 43 mm

In the ARF version of tower trainer 40 you cannot change the mount, I was looking for something similar with the same bolt pattern but didn’t find.

61 FX will not fit into tower trainer 40 ARF engine mount.

Alex

opjose

Not true.

You'll have to plug the existing holes to do it, but you can fit other mounts in there and get the FX .61 in.

I have a friend that has one set up this way.