Planeclothes

My Feedback: (1)

I recently purchased a Peakmodel 50 size Edge 540 which I am presently putting together. I mounted a brand new DLE 55 using the stock standoffs and when I put the cowling in place found that the prop drive washer is more than 1/2" BEHIND the cowling's center hole. On top of that I also observed the cowling looks off centered relative to the engine's center line. Obviously the firewall has some right/down thrust built in but the cowling's ring was not offset for that. Bottom line is I need to use 1/2" (or slightly more) spacers and some washers behind the cowling ring to get better centering. I stopped by Home Depot today and picked up (4) 1/2" long nylon spacers and (4) 5mm x 40mm bolts. I also purchased a 4 ft long 3/4" hardwood dowel. This is my first project with an engine larger than 30cc and I am fully aware of how much more vibration a larger engine produces. My question is, would it be safe to use the nylon spacers (easy way out), or should I cut spacers out of hardwood?

Bass1

Not sure how long the stock DLE standoffs are but I've been using those "hardware store" nylon spacers ( total standoff length @ about 1.5 inch)) on planes for years with no problems. Of course I still crash em' daily and don't know why !

BarracudaHockey

My Feedback: (11)

McMaster Carr has threaded standoffs in a number of sizes, as does SWB that are aluminum.

Cyberwolf

My Feedback: (4)

Hi
This what I would do, Make two smaller firewalls from 1/4 aircraft grade plywood that will cover the hole spacing for full contact plus on the standoffs, Glue the two together and set aside for now.Put the engine and cowling in place and measure how far off the center of the cowl is off both ways and write it down, a quick sketch may even come in handy. Remove the engine and cowling then plug the previous holes that were drilled with a 1/4 inch hardwood dowel cut to the correct length, and glue in place. You may need to run a drill through the holes to enlarge the holes to 1/4 inch.
Glue the spacer firewall in place making sure that it's centered and clamp and let dry. Mark the new correct hole spacing and redrill the holes for the standoffs, put it back together and see how things line up. if you measured correctly it should be dead on.
The extra plywood won't weight much and doubt you will even notice it on a plane of this size.
Here is something that TOM use to say time and time again he wouldn't use the stock standoffs that came with engines. He used just what you bought a 3/4 inch hardwood dowel cutoff to the proper length then drill the hole though them.

A person could also just fill the 1/4 inch holes and cut new standoffs from the hardwood dowel and forget the extra plywood on the FW.

Myself I refuse to use washers and shims to get my engines in line with the cowls, Just something else to wear and cause the bolts to come loose even with locktite, but the main reason is the fact it puts a bind on the engine case, which can lead to serious issues down the road. Busted off mounting ears,warped cases that create leaks and a poor or non running engine are a couple of reasons the list goes on.

Zippi

My Feedback: (10)

Chief Aircraft Inc. has some 1/2" stand offs.

http://www.chiefaircraft.com/radio-c...standoffs.html

pe reivers

Whatever it needs to securely mount the engine.
Run it, and check frequently. If it holds well you did the right thing!
So many roads lead to success.

Whistling Death

Hardwood dowels work like a charm.

tande

My Feedback: (48)

If I understand you correctly, you will need a standoff distance of approx. 3-1/4" (stock "DLE" stand/offs I believe are 68mm plus your 1/2" or more).....seems like a lot to me.....I would contact "Blazing Star Mounts" ( [email protected] ) & have a talk with him about a CNC "Box" mount......FWIW

acerc

I use 1" hardwood dowels cut to fit without the DLE standoffs. I have a couple of them at 2-1/4" long, and they are as solid as the day I put them in which was a couple years ago.

tande

My Feedback: (48)

That's good to hear!......but going from 2-1/4" to 3-1/4'" is another 30%....just not my style....FWIW

Planeclothes

My Feedback: (1)

Thank you all for your comments and suggestions. Right now I am caught between doubling the firewall with a single piece of 1/4" plywood and then add 1/4" to 5/16" hardwood spacers or just cut 1/2" to 9/16" hardwood spacers. I like the idea of the extra 1/4" plywood on the firewall better, but the firewall was already fiberglassed and that makes it a little more complicated. Yes Tande, 3 1/4" sounds like a lot but consider I am only adding about 1/2".

MTK

Curious, why not just get a set of new stand offs that are the correct length? McMaster Carr sells aluminum hex stand offs up to 6" long. They are inexpensive and come in various thread sizes including metric. In the end, i'd bet this is your best, lightest, simplest approach

BarracudaHockey

My Feedback: (11)

There's an idea!