Firewall Reinforcement
 

I am building a Hobbistar 60 and am going to upgrade the nose gear with a Fults nose gear. What are some recommendations of reinforcing the firewall due to the additional stress possibly caused by the heavier nose gear? Thank you.

RE: Firewall Reinforcement
 

There are a couple of good ways to strengthen the firewall. The first one is to epoxy tri-stock into the corners where the firewall meets the sides of the fuselage. The second way is to drill holes through the fuselage sides into the firewall, then epoxy wooden dowel "pins" into these holes. Then shave off the dowel and sand it flush with the sides of the fuselage. Both of these will give you a lot of added strength.

Ken

RE: Firewall Reinforcement
 

One of the best ways to reinforce firewalls is to glue (with epoxy typically) one or two layers of fiberglass cloth over the area you want to reinforce. You can buy 6 ounce fiberglass cloth at Wal-mart in the automotive section. Soak the glass cloth (on a piece of waxed paper) with epoxy, squeegee off the excess glue, then press it on over the area.

RE: Firewall Reinforcement
 

Is this your first trainer/plane? I always use triangular stock epoxied to the back of the fire wall. IMO I would leave it the way it is and mount the gear, if it breaks because of a hard landing, reinforce it then. It should hold up under normal landing conditions[X(] :D

God Bless!

RE: Firewall Reinforcement
 

It's not the WEIGHT that will cause the problem, it's the increased stiffness. It will not flex as much and absorb a poor landing like a softer wire gear. THIS is why you need a stronger firewall, because more stress will transfer to it.

RE: Firewall Reinforcement
 

Or, don't land like I do.

RE: Firewall Reinforcement
 

The fults though heavier should be less stressful due to the less stiff coil spring.
I reinforce with a wood frame behind the firewall as previously described, but I use hard wood as I don't believe balsa has much strength. Use at least 1/4" square.

RE: Firewall Reinforcement
 

a different question
which parts i shouldn’t reinforce?

other thoughts....
because in a shallow, slow nose crush i prefer that only the firewall will be damaged, its easy to replace.
if the firewall is strong, other and more expensive things will brake.
i mean Firewall Reinforcement for when its really weak and flimsy

thanks

RE: Firewall Reinforcement
 

I reinforce the firewall because of engine thrust., I overpower most my planes and worry about pulling the firewall loose.

RE: Firewall Reinforcement
 

Yeah..... :D
i know what you are talking about, thats why this toughts of not reinforcing came up....

RE: Firewall Reinforcement
 

qusetion ? how thick is the fire wall
how heavy is the plane .what engine did you use

RE: Firewall Reinforcement
 

I like the dowel reinforcement suggestion, this is a great idea. In the past I've reinforced the lower firewall following hard nose landings using wood from yardsticks (also great for wing spar repair) Cut a custom formed piece of yardstick wood to fit behind the firewall, use epoxy plus drill two small holes to bolt it to the firewall with small nuts and bolts.

RE: Firewall Reinforcement
 

BLUE SKY
NO OFFENCE BUT THAT SOUNDS LIKE A HAK JOB . YOU DIDNT SAY WHAT ENGINE YOU ARE USING HIGH TORQUE OR LOW
WHAT I WOULD DO IS TO CUT THE FIRE WALL OUT IF THIS IS FOR A 60 SIZE PLANE
THE FIRE WALL IS MOST LIKELY 1/4 in
TAKE <2 > 1/4in FIRE WALLS EPOXY THEM TOGETHER REINSTALL IN THE PLANE
WITH 1/2 in TRIANGLE PINE THEN USE 1/8 DOWELL DRILL AT AN ANGLE FROM THE FIRE WALL TO SIDE OF THE FUSE AND EPOXY THEM IN CLEAN EVERY THING OUT BEHIND THE FIRE WALL AND PAINT POLYESTER RESIN THEN DRILL ALL OF YOUR HOLES FOR THE HEVY DUTY NOSE GEAR A LOT LIGHTER AND STRONGER

RE: Firewall Reinforcement
 

After reading this post, I cound not remeber if I had added extra reinforcing to my SkyBolt ARF. I went out and checked my SkyBolt. It felt loose after the last time I flew it. Grab the engine cone and pulled back and forth to see if it was loose. It came off in my hand ! The firewall came right off the plane.
When I assembled this ARF I could`nt get to the firewall because of the way it is put together. Now I can LOL! Better for it to happen in the shop than under power.
Thanks guys, this post saved me a plane.

RE: Firewall Reinforcement
 

The strongest setup is to set the firewall back about a 1/4 in so the sides of the fuse are forward of the firewall, then put triangular stock in the front and back corners of the firewall. When you stop and think of it, when you pry back on the landing gear, the top of the firewall is being pushed forward. The triangle pieces on the front will strengthen this a lot. For the triangular pieces, with the grain of the wood going vertically in the corners the triangular pieces split fairly easily. Buy a piece of 1/2 in thick balsa and put the end of it through the bandsaw cut on a 45 degree angle. Make a bunch of pieces. Glue these trianglular pieces in the corners and you see where the grain goes across from the sides to the firewall. Much, Much stronger joint. Trix learned from scratch building since the 60s:D

RE: Firewall Reinforcement
 

Six Guns, no offense taken. Using a yardstick as hardwood in a model was a tip given to me by a U.S. National Scale Champion. I'm sure he wouldn't take offense either. ;)