IMAC Dalton 300 ml build thread.

[fencelake]

yep, even twins, in my opinion, should not use standoffs, no matter what the size.
for 50 cc and under, might be ok, but for anything bigger, standoffs are less able to dampen the vibrations of a 2 stroke.

Well, I kind of wanted to paint in front of the firewall anyway... now I have an excuse to take it all apart!

 

[orthobird]

That's good news!! I've seen that recommendation for my engine as well (DA-120). It's brand new, so there's going to be vibration... so I'm going to wait a little while, but it's really supposed to help.

right now, you have standoffs?

 

[fencelake]

right now, you have standoffs?

Yea... That's how it came when I bought the plane. They're really short and it's mounted solid. Flies great!

 

[orthobird]

I would leave it alone!!
In my case, the airplane is super smooth, i have never seen an airplane "not shake" like this one. But, once the RPM gets about 1200, it would start to shake and vibrate.
Now, the RPM gets to 900, and the shaking is way less. At 1200 or 1100 rpm, there is no shaking!!

I am considering making this block, instead of plywood, out of aluminum.!! this will be fun to do, kind of like the old mount extensions that they used to make, something called, i forgot, blazing star or blazing saddles!! LOL. I forgot which!

 

[fencelake]

I would leave it alone!!
In my case, the airplane is super smooth, i have never seen an airplane "not shake" like this one. But, once the RPM gets about 1200, it would start to shake and vibrate.
Now, the RPM gets to 900, and the shaking is way less. At 1200 or 1100 rpm, there is no shaking!!

I am considering making this block, instead of plywood, out of aluminum.!! this will be fun to do, kind of like the old mount extensions that they used to make, something called, i forgot, blazing star or blazing saddles!! LOL. I forgot which!

Well, now... I don't know if I can leave it alone! Half the reason I'm in this hobby is to not leave things alone! Hahaha!

 

[orthobird]

LOL~~~ gotcha~! me too!

 

[orthobird]

Will be removing that plywood mount, looks like it has deformed and now i have up-thrust, airplane is not flying well.
I started building an aluminum mount.
it is not finished. I just dropped it off at a friends house, he will finish it off. I will post pictures of the final product tomorrow. Goal is for it to be under 9 ounces.

 

[mndless]

Geez !!! Looks like you are milling out an engine block there.... impressive undertaking !

 

[orthobird]

it started out like this:

6061 aluminum
4" x 4"

 

[orthobird]

then i cut 45 mm off one end: