Help on engine cowling?
 

Hi everyone, this is my 1st post here and I am hoping to get some help?

I am 3/4 of the way through building a 1:6th scale P51 Mustang.

a rough review of the build can be seen here

http//www.airbornemagazine.com.au/constructreview/p51/

I am having trouble knowing how to attach the engine cowling to the main Fuselage. The fuselage is made from Balsa with ply bulkheads.
I have fashioned the cowling from Fibreglass in one piece. So, it has to be attached at the back end of the cowling, There is nowhere else to screw it on.

So, my question is!!
What is the best way to attach the Fibreglass Cowling? I thought maybe I could use some Aluminium angle screwed to the front bulkhead??
The only way I can think of doing that is with self tappers and the Fibreglass cowling won't handle that type of pressure for very long.

Can someone here assist me with your best practice for doing this job because there are virtually no instructions and I'm reasonably new to building model aeroplanes.

Thanks for any help! and Hi from Australia!!!

RE: Help on engine cowling?
 

Usually the cowling slides onto the fuselage by about an inch or two. Then a system similar to that shown in this link is used.

http://www3.towerhobbies.com/cgi-bin...P?I=LXWDH0&P=8

Good luck,
Bob T.

RE: Help on engine cowling?
 

Thanks for that!

Funny! plastic is the last thing I would of thought of.

Thanks again

RE: Help on engine cowling?
 

Hi!
Those would not hold it long! Problem is vibrations.
A much better way of holding a cowl is doing it like this.
3mm epoxy plates glued (24 hour epoxy finnishing resin and cut glass/carbonfiber ) inside the cowl using four metal screws screwed into the firewall. The cowl is secured through the front using a long screw driver.

RE: Help on engine cowling?
 

Let me see if I got this right...........................

1 Make 4 fiberglass supports

2 Epoxy them or glass them to the INSIDE of the cowling

3 then, screw those supports to the firewall of the fuselage??

Is that right??? If I am right, th eobvious weak points would be where the supports are glassed onto the COWLING, yea???

Thanks again for any help!

RE: Help on engine cowling?
 

Yes, the weak point or shear point would be at ther attachment to the cowl...but, if properly attached and glassed to the cowl with proper preparation this is a viable, time tested method of mounting. Since there should be no flexing of the arms when they are secured down flat on the firewall and there is no appreciable force acting on the cowl they are not likely to break off.

RE: Help on engine cowling?
 

Hardwood blocks, self tapping screws, and bonded or sealing washers on all the screws.

RE: Help on engine cowling?
 

I solved a similar problem on an ME-109 by epoxying hard wood blocks to the firewall and than mating hardwood blocks to them with large screws and blind nuts. This assembly is sanded to fit the inside diamiter of the cowl. You can access the screws when you remove the spinner. I then slide the cowl on make sure it is postioned perfectly and then tack glue the outside blocks to the cowl. You then remove the cowl and epoxy the blocks in permanently. No exposed screws. You will need a long screwdriver, but thats easy.

Regards,

Dave

RE: Help on engine cowling?
 

Thanks again guys!!!

Great ideas there for me to work with!!!