I am thinking about getting a DP Ultimate 120 and using a YS 1.40L for power. Of the planes I have seen, the firewall does not appear to be of highest quality ply. In order to provide better strength has anyone glass'ed the inside of the firewall and surrounding joints... or just used a shock absorbing motor mount? Also, has there been a problem with the flying wire attachment points and do they need to be reinforced? Has anyone tried to put the fuel tank over the CG and has it had any noticable effect? For those who have gotten the ARC model has it been just for custom covering or have you made changes better made before the film goes on? Any other quality/safety mods or replacements that anyone has made would be appreciated.

I fly mine with the 140 and have had no problems, if I remember correctly, I epoxied triangle stock behind the firewall where there wasn't any. I am using the stock engine mount.

I have a saito180 in mine. No firewall problems but within about 10 flights my elevator hinges broke (2 out of 3 on on side) I was wondering why I had to keep retrimming elevator on that flight. Not sure if CA hinges are the best on those huge control surfaces, however I do always use to much CA when installing, just can't help it, the bigger the glob the better job (not). Do you want to buy one??? Only 10 flights on mine. By the way my tank is mounted over CG with perry pump on motor. I did this at the start, mine has a 24 ounce tank and that just seemed like a lot of weight up front when full. Nice flyiing airplane, I just have to many new projects going, need to free up some money to finish a couple other planes that are on my pool table, since my hobby room is full.
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Thanks sheif83274 for the info. I read a post on rcu were someone described a home made jig for drilling robart hinge points equally aligned on matching surfaces. I don't have any experience with hinge points but I am keeping it in mind. I have used a wax crayon on the center line of ca hinges to help keep them from absorbing the glue. No sure how effective that method is... or how to tell. Does anyone know if the ys 140L has enough pressure to draw/pump fuel with the tank over the CG and are there any issues involved. I am planning on using a tertra tank and probably wrapping it with tape and then put that inside a baggie.
Thanks Mspohn for the info. Triangular pieces sounds like a good mod that has no significant weight penalty. Do you use any special fueler or just fuel dots? Did you add any tail weights?

I used dubro clevis's and rocket city (blue) ca hinges and cut most of the ply out of the tank hatch. The firewall sems plenty strong to me

i took 1/8 dowel and pinned mine in a few places as i did a gaser on it at one time its now back with a os 160.

What's the best muffler and method of running exhaust on the DP Ultimate with a YS 120? I suspect that little bulb muffler is pretty popular. But, no smoke capabilities. If I want to add smoke, what's the best combination? Anyone have any pics they can post?

Thanks.