WMAC Group build - Impressivo

I’ve finished the construction phase of my impressive model, received my electrics so now looking at installing it all.
However, the first thing to strike me is the motor cooling provision in the kit is based on a mega motor using straight thru axial cooling air flow using 4 holes in the front and four holes in the rear.
The TGY motor has a centrifugal cooling fan. Consequently most of the cooling air will exhaust from the rear sides of the motor. Although this motor has some rear cooling holes, I am wondering if this will provide sufficient clear airflow. I suspect most of it will not be expelled efficiently but just circulate around the fuselage.
I don’t have any direct experience on this matter to know if this will cause overheating but to be on the safe side I would like to seek other group builders views on this.

A possible solution would be to install an extra bulkhead to separate the inlet and expelled cooling air, then open up some cooling holes behind this bulkhead. see photos.

My personal view is that cooling will be minimal regardless of mega, turnigy or what have you. I will simply fit my motor and forget about it. Your retro-fit solution might be of benefit and if my motor burns up and dies long before yours I will do something about it when I buy a second motor.

My motor has arrived as well. Think I'll do your mod, Kevin. Are the two extra holes repeated in the bottom, ie one for each motor vent?

Being new to all this electrical stuff, what would you experts do with the motor mounting. 2mm ply seems a bit thin for a horse power. Would an extra sheet of say 16" aly over the rear face help longevity, or maybe another sheet of ply? Should one use thread lock on the screws (not supplied)?

While I'm asking questions, how should we restrain the battery? Would velcro straps be best for holding the batt? I take it a foam bed is not preferred for these hand-warmer power packs.

I am thinking of beefing up the internal floor a bit before cladding the fus. Before anybody says 'owt, my landings were perfect today.

If there are any tips available, they would be appreciated.


Phil

Just been checking Fuz bits, 1/4 sq extremely hard, does not wish to bend to shape. Tried soaking, but not good. Might have to raid scrap box for something more suitable.

Stuart

Electric motors do not vibrate so 2mm ply will be fine. I have some 2mm screws which I can bring along to the next meeting. Thread lock not required...again, no vibration. Velcro straps are fine for battery restraint. Foam be is fine too, the battery will not get very warm. Not sure why you would want to make the model heavier by beefing up the floor? Heavier means faster landings which means MORE chance of damage.

Tips? Just one. Assume the designer knew what he was doing and build it as designed

Phil-C wrote: My motor has arrived as well. Think I'll do your mod, Kevin. Are the two extra holes repeated in the bottom, ie one for each motor vent?

Phil - Yes i have now added two holes on the lower surface - I have also replaced those sections with 2mm ply - Look closely at my pics - kevin

While I'm asking questions, how should we restrain the battery? Would velcro straps be best for holding the batt? I take it a foam bed is not preferred for these hand-warmer power packs.

I am thinking of beefing up the internal floor a bit before cladding the fus. Before anybody says 'owt, my landings were perfect today.

Phil see attached photo showing a very light reinforcement to false floor - That should be enough to support a velcro strip and prevent the floor being ripped out when removing the battery

Phil

Stuartmck wrote: Just been checking Fuz bits, 1/4 sq extremely hard, does not wish to bend to shape. Tried soaking, but not good. Might have to raid scrap box for something more suitable.

Stuart

Hi Stuart - Yes i found the same with some of my 4mm (3/16) longeron stock -I actually cut and spliced some of it to place the hard section at the rear and the softer sections for the front curvy bits

The extra strip of 4mm sq was what I had in mind, Kevin. Also use of 2mm ply top and btm at the rear.

RE - top or bottom elevon hinge - I have gone with lower servo / elevon horns as per manufacturers preference but feel safe because i am installing metal gear servos. - The attached picture shows the clearance.

Yes, I did mean the 3/16. When you get to my age, you remember things as being bigger than they are/were! Finally managed by soaking and weighting to get them near to shape.
I agree with Mike re motor mtg, with the size of the former, apart from lack of vibration,most of the strain will be taken thro' the fuz sides - build as per plan.
All on hold now, am away for a few days.
Happy New Yeat to all.

Stuart