jmb52760

Good points Dave. I do like shaping the fuse with a razor plane. It's like making a sculpture. It's very satisfying to see a balsa box turned into a shapely pattern plane fuselage.

I noticed that the block of balsa in the nose has the grain running crosswise per the plans. I always install all of the wood that I'm going to carve with a razor plane with the grain running fore and aft. (I've never tried to plane wood across the grain, is that even possible?) I doubt that there will be any significant loss of strength if I change this block for a block of the same shape with the grain running fore and aft.

Mitch

jmb52760

After reading through the post that Dave (Dbacque) linked on the first page of this thread, I've decided to change to an OS .55AX for power. I have one on my Deception .40 and it is doing well. It is flying with a stock muffler. I'll probably put an aftermarket pipe on this Dirty Birdy.

jmb52760

I picked this back up. Here are some fuselage interior shots. I deviated from the plans for the servo location and mounts.

jmb52760

Stiffening the trailing edges of with 1/32 inch plywood. Slots were cut on a Emco Unimat mill with a dremel cutoff bit chucked. This setup is shown in one of my previous threads. I can add a pic here if interested.

The plywood will be cut flush with the TE after the glue sets of course. Then the blocks will be glued to the wing and stab and shaped.

immelman50

I think the 55 AX is a good choice. I'm happy with the weight of mine with a heavier OS 61 FSR in front, but had to use about 4 ounces of tail weight to get it to balance. With fixed gear ( which I would use if I built another, one by the way), you should easily be around 6 pounds. Dave mentioned rib issues around the landing gear blocks. I have had them, too. My set up is different because of the retracts, but the rails I mounted them on are similar in how they attach to the ribs and in the same location. The ribs can split chordwise ahead of or behind the ply, this allows the ribs to push the sheeting up and get loose. I didn't have any trouble til recently and haven't ever had any real hard landings. It seems to be a problem that develops over time in my case. I would recommend making the rib ply all the way from the spars back to between the trailing edge sheeting or laminating a piece of thin ply to it in place. I hope it isn't too late for that. Probably not an issue on paved runways but I fly off fairly bumpy grass.

Another fix , but not in line with classic build methods, is a piece of carbon fiber glued to the sides of the rib vertically to prevent that splitting I mentioned. I did it this way because it was easier in a finished wing and so far it has been solid.

immelman50

I realized should have been clearer as I reread the last post. I have the same ply piece on the sides of the ribs as the kit shows, what I meant for reinforcement would be applied on the other side of the rib from the current ply piece if that piece is already in place . If not the kit piece could be replaced with a spar to trailing edge ply lamination onto the balsa rib. The splitting was ahead of and behind the kit ply piece that the gear hardwood piece slots into, so a longer ply reinforcement would solve it at a minimum weight penalty. Certainly less weight than repairs would add if you get the same kind of splitting.

KLXMASTER14

I agree, the .55AX is an excellent choice for the DB.

FWIW, I tried a Mac's 8.5cc muffled pipe, and a 10cc quiet pipe, the 8.5 gave more power, but was very peaky, used a lot of fuel, and the mid-range was very rich. The 10cc quiet pipe gave up a bit of boost, but gives a much more useful power band and throttle response, as well as a reasonable fuel burn. Note that the quiet pipe vs. muffled pipe vary in their construction, and most assuredly accounts for the difference in operational characteristics.

-Robert

jmb52760

Thanks for the excellent tips guys. I'll try to do some reinforcing of the landing gear ribs prior to covering. I think I could just put in a layer of light fiberglass on the side opposite the plywood doubler.

As for the choice of pipe, it's good to get first-hand experience. May save me a step.

jmb52760

Ready for Maiden. I decided to just cover it and get it done. It's a little rough but I'm sure it will fly just fine.

Timthetoolman1

My Feedback: (6)

HA, good job. I'm still messing with covering.
Looks like you siliconed your exhaust?

Hope you get a video of the maiden.

Tim

jmb52760

Siliconed my exhaust? I'm not sure what you mean. It's a brand new OS 55AX with stock exhaust. I'm planning to use the Mac's 6720 after break-in.

Timthetoolman1

My Feedback: (6)

Some guys use RTV silicone to seal their exhaust, just thought I saw that on yours.

I'd like to try that 6720. I think I'll break in mine on the ground and use it. Let us know how it runs after the change.