Hi,

Idecided to try an end grain balsa standoff for my motor.

The previous standoffs where 2"aluminumlegs, with a 1" foot print each. See pic.

The balsa standoff is 2" tall and has a 3" square foot print.
There is a 1.5" lightening hole through its center.
It's been soaked in thin CA and caped on the motor side with 1/64 aircraft ply.

The Aluminum standoffs weight 3.68oz.
The balsa block weights 2.56oz.

For testing, so far I have put it between twometalplates and jumped up and down on it. Iweigh 250lb plus and in measuring it, there was no compression.

Mounting the motor to the firewall with it, it feels solid and again, no measurable compression.

If I can get the retrofit of the pipes completed this evening,I plan to run up the motor tomorrow and if that goes well, do a short easy going flight, land check it, then a more robust flight working up to high speedgyroscopicswith a 28-10 solid CF Bolly. If that doesn't cause it anygrief, I think it should be good to go.

Branwell
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I am curious how you mounted it to the firewall?

Hi Jake,

Being the cautious type, for the first go round, I through bolted it with 1/4-20's and jam nuts. If it works out, I'll go to a smaller bolt.

Thanks for the hint by the way, on the water bottle fuel tank. One is definitely in my future.

Branwell

Cool good to know.</p>

Ya the water bottle tank is great. 40oz dubro vs 1 litre (33.1 oz) bottle was 5oz savings if I recall correctly If you find a Fuji water one they are square and mount super easy.</p>

Mine survived a pretty hard crash after snapping a wingtube which was nice to see. Infact it will be used in the next plane. Strong little suckers </p>

Hey Jake, why don't you start a thread here on them water bottle tanks?

Branwell
Your balsa block stand off is a great example of  using a material we all are familiar with and don't have to have a small milling machine to be able to create stronger yet lighter mounts. I'm surprised that someone has not come up with one that is made of carbon fiber. Opps maybe I just killed my statement about using an old standby like balsa. Any way Branwell I admire your thinking and creativity.
Water bottle fuel tank? What's up Jake??
Terry<br type="_moz"/>

Hi Terry,

I'dlove to take credit for it, but Ireadabouta guy that did it with a DA-85 single and a DA-150 twin. If it will work on those,speciallythe single, it should have an easy life under my motor.

For firewalls,about 10 years ago, I hung a Quadra 100 off a 1/4 inch thick end grain balsa carbon fiberlaminate. Put over two hundred flights on it with nomaintenanceat all. If Iremember correctly, it weighed less than quarter the weight of theoriginalpart.We also used it for landing gear plates.

Balsa is some pretty amazing stuff.

Branwell

I read somewhere that Balsa has the highest strength to weight ratio compared to many woods. Even Douglas Fir which is used for house rafters and floor joists.

as suggested I started a thread on the water bottles.  You can find it here  http://www.rcuniverse.com/forum/m_87...tm.htm#8781355

Igot the pipes installed and ran the motor on the balsa standoff.

After a 5 minute run, Iwas able to retighten the motor bolts about an 1/8 of a turn. Ran it for a further 10 minutes and no further tightening was needed.

Seems like any other new mount, so my plan tomorrow is to fly it and see how it holds up.

Branwell
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Branwell
Sounds great. Keep us posted.
Terry

Lazer,</p>

The C/F mount has already been done for a 3w 157.  It worked out that by the time it was done it would cost over a grand to make when done in the usual manners and having to purchase the materials.  That sorta puts it out of the usual modelers budget....</p>

Hi,

Igot 8 x10 minute flights on the plane today.

Did my best to fail the balsa mount, but the motor did not fall off.

Was it asuccess?

Itook the cowl of three times and each time, was able to tighten the bolts about a 16th of a turn.

This might be normalsettling, on the other hand, it might not. Idon't know, so am not inclined to call it asuccessyet.

Branwell
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I wouldn't be alarmed by that, but you definitely should keep checking. Even solid aricraft type plywood compresses and bolts need to be retightend frequently.

Hi,<div>
</div><div>After the last two flights yesterday, I packed up and went home without checking the engine mount bolts.</div><div>Today I had the plane apart making some changes and checking the bolts, to my delight, no tightening needed. Perhaps I reached the end of the compression.......</div><div>
</div><div>Branwell</div>

I figured that would happen. Sounds like this is a good idea to me.
Terry

To those of you interested in such things.........

Igot another 50 minutes air time on the balsa standoff doing a lot of gyroscopicmaneuvers. There has been no further tightening needed.

On this setup:

BME 116 on pipes, 2" End Grain Balsa, 110" Extreme Flight Yak.

Iam thinking its a success.

Branwell

I never doubted that it wouldn't be a success. Congrats!
Terry