WH-300 3-Amigos build thread (3 ways of doing the same thing)

[SleepyC]

EMO? I am too old to even know what that really is!

Kiss is just good rock and roll...!

[OverTemp]

Are going to re-inforce the firewall? How? Can't really fiberglass this one.I'm thinking some hardwood tri-stock pinned through at a 45 degree angle. Maybe on balsa or hardwood tri-stock on top and bottom too.

[Greyhoundman]

UM.....cough....cough......



Let's see it.

[KrisW]

	Quote: Originally Posted by Greyhoundman
	UM.....cough....cough...... Let's see it.

Patience Greyhoundman-san . . .I don't even have a PLANE yet ..

As for reinforcing the firewall and doing other things, we'll see what is going on when the plane gets here. I'll probably just use some aluminum angle around the sides. top, and bottom of the box, JB welded in place and screwed down with #4 screws. That setup is bullet proof.

But, again . .wait and see.

[OverTemp]

	Quote: Originally Posted by KrisW
	Patience Greyhoundman-san . . .I don't even have a PLANE yet .. As for reinforcing the firewall and doing other things, we'll see what is going on when the plane gets here. I'll probably just use some aluminum angle around the sides. top, and bottom of the box, JB welded in place and screwed down with #4 screws. That setup is bullet proof. But, again . .wait and see.

JB weld, eh? I've never even thought to use that stuff on wood! Sounds like a good idea.I think when you get the plane you'll see the aluminum angle won't work around the outside... the firewall is recessed into the motorbox sides and tabbed. You could do the inside... I should probably just wait 'till you get your plane.Off topic... I got my MTW cans second-hand from a friend. One has a small crack in it from a bad mounting job. It doesn't look like it ever leaked and he said he flew wth the crack for a long time. Is is OK to put a spot of JB Weld on it so seal it? Will it stand up to the heat?Also, these will be my first cans. I know I'll need to seal the cannister mounting area off from the fuse. Is 1/16" balsa needed or can I go with paper-thin 1/32? Not sure what the heat required. Let me know when you get your plane.Finally... since you've run so many cans/pipes... it is best to open the covering the entire area under the cans or just an area at the back? I probably wouldn't even need to cut much out under the cowl if I opened the cans all up.Thanks

[KrisW]

	Quote: Originally Posted by OverTemp
	JB weld, eh? I've never even thought to use that stuff on wood! Sounds like a good idea.I think when you get the plane you'll see the aluminum angle won't work around the outside... the firewall is recessed into the motorbox sides and tabbed. You could do the inside... I should probably just wait 'till you get your plane.Off topic... I got my MTW cans second-hand from a friend. One has a small crack in it from a bad mounting job. It doesn't look like it ever leaked and he said he flew wth the crack for a long time. Is is OK to put a spot of JB Weld on it so seal it? Will it stand up to the heat?Also, these will be my first cans. I know I'll need to seal the cannister mounting area off from the fuse. Is 1/16" balsa needed or can I go with paper-thin 1/32? Not sure what the heat required. Let me know when you get your plane.Finally... since you've run so many cans/pipes... it is best to open the covering the entire area under the cans or just an area at the back? I probably wouldn't even need to cut much out under the cowl if I opened the cans all up.Thanks

Okay. . .first issues first.

Keeping heat out of the fuselage. . a 1/64th ply "wall" is plenty thick and strong enough for the task, a lot more resilient and tough compared to any kind of balsa out there, and can be fashioned with scissors.

JB weld for sealing a crack on a canister .. just go to your local automotive parts store, and get a pack of "Muffler tape", and wrap the entire canister with it in the area of the break. Once it heats up one time and takes a set it's permanent. If the crack is toward the aft part of the canister, you can use the muffler wrap as a reinforcement to mount the canister, and it will help keep the thin aluminum from denting or collapsing.

If all you want to do is mend the aluminum, use muffler "putty" over the affected area, after roughing it with 100 grit sandpaper, and it will effectively seal the crack, and should be a permanent fix.

I always leave a good sized area for warm air to exit the pipe/canister tunnel. It's very easy to rebuild the area in the belly if it is just stringers and covering, by cutting some 1/16 balsa sheeting to the proper shape, then ironing the covering to it in place and then CA-ing the balsa to the stringers. After that, cut out the opening you want, afix a small airdam to the front of the opening (to create a low-pressure area), and finish mount the canisters in place. You need an area about 1.5-2 nches front-back and as wide as most of the belly if possible to get the air out efficiently. If you are worried about heat affecting the covering near the outlet, you can mask it off, rough it with some scotchbrite, then paint the area with some "texture paint" of the color of your choice. The texture paint is very thick, reasonably flexible, and will make an effective heat block layer between the exiting air and the covering.

This is the technique I plan to use in my 41% 300 when I install the full length pipes. It's proven itself over time, and works very well for a reasonably small amount of effort involved.

[wildhare]

I can tell you what we have done in our testing.

We used standard canisters (I think they were MTW TD110k but I'm not sure). We mounted them in the tunnel and did not seal anything. We opened up the holes in the bottom which are already prepared, just cut out the covering.

If you use rear exit cans the exhaust can come out the back and out the bottom, and this makes putting the cowl on simpler.

The air naturally flows over the mufflers and out the rear vent. We flew our test plane probably 50 flights thsi way, in hot Texas weather, and never experienced any real heating issues either during or after the flights.

If you want to seal it fine, but I don't think it's necessary. I also used this technique on an older 35% Extra which did not have a tunnel at all. The canisters were exposed inside the fuse in front, still no real heating issues aslong as there is airflow over the mufflers with an exit ahead of the electronics.

One problem we did have was the canisters blowing off the headers. You will need a stop at the rear of the can to keep it from sliding back.

TF

[OverTemp]

Did you get oil and muck inside the plane? With the front exit cans that I have I'm worried oil will blow back into the fuse.

[3-d flyer]

can anyone who used pro-links tell me what sizes are needed on this plane? I am getting gear together now, and do not want to wait, i still need a few servos yet..... so i have not mounted them yet to find out..... I'll be using the H9 (rocket city) hardware and balllinks....... Thanks

[airborneSGT]

I can check tonight when I mount up my servos. I am going to be using the hardware kit that Tom provides so I will have the composite push rods.

[KrisW]

You know. . .it's eerie. .

You walk into a warehouse that is 150 yards long. . scan the shelves, and inside of 3 seconds can spot YOUR airplane. . at the far end of the place, some 80+ yards away. It's in a silly box, you can't read the labels. but you KNOW. . that box. . down there, and the one next to it, are YOUR airplane ! !

I've been in this hobby too long. . . . .

[KrisW]

so. .. I get home with these silly boxes. . and I open them. . and take out the stuff inside. . and am VERY happy with what I see ! ! !

So I quickly put the main gear and tail gear on the plane, slide the rudder hinge shaft into place, mount the stabilizers, bolt on the cowl, throw a pair of wheels inside the fuselage, add the hatch and canopy and weigh it without the wings.

15 lbs 1 ounce

and the wings and tube are:

7 lbs 3 ounces.

Okay. . that's our starting point.. . .22 lbs 4 ounces.

to this I will add:

DA-150 w/KS 1090 pipes, headers, Petes Models spinner and Biela 29-12 3-blade prop: 12 1/2 lbs (or so)
Radio gear: 10 standard sized servos, 2 jumbos, 2 receivers : 34 ounces (2 lbs 2 ounces)
Linkages and rigging: 1 lbs
Electrical gear: 3x7 ounce batteries w/switches and wiring: 28 ounces (1 lbs 12 ounces)
Fuel system: 12 ounces

total:
22.25
12.5
2.1
1
1.75
.75
_________
40.35 lbs without Pilot or IP. Call it 40.5 lbs Dry.

I think that's a pretty accurate figure to shoot for.

Let's see if we can break the 40 lbs barrier. . . . .

[RC_Pattern_Flyer]

OK, so here we go, back in town and so far i have reinforced the firewall the same way that Tom advises in the manual. I soaked all the joint with THIN ca until the wood soaked no more. I then cut triangle stock and epoxied it top and bottom from the inside of the plane. The front is already supported with triangle stock. I then drilled a large cutout in the center of the firewall and mounted the motor using a butterfly fastener which allowed me to place the cowl on the plane and slide the motor around until the spinner lined up with the cowling and ten tightened down, removed the motor from the support plate and drilled accordingly.

i am sorry but i was having trouble with the camera during this process but did get some pck of the plane as it came out of the box.

[RC_Pattern_Flyer]

As for setup, the basics are similiar to everyone else, in some cases, i had a few items that had outstanding availability and will do the job just fine.

Motor: 3w140 (hog of a motor, used to hover with ease 45 lb edge540)
Prop: Menz 30X10
Spinner: www.espritmodels.com only 38 bucks for a carbon spinner with light backplte

Recievers: Dual Futaba R149D
Power: Fromeco Dual 4800 mah for radio, 2DogRC lipo for ignition 1800 mah
Fromeco Failsafe Switches all around and Fromeco Regulators
Servos: 6- Hitec 5645MG in the wing (already have them)
2- 8611A (one on each elevator half)
2- 8611A (one on each side of fuse pushrod setup for Rudder)

I will be running standard exhaust.

WHEN the new carbon gear comes out i will seriously consider adding it to the plane, i am hoping for around 38 lbs dry.

More to come.

Chuck

[KrisW]

Good job RC patternflyer. .

And now. . here is how I did it:

Pics explain most of it. Basically I found center of the motor box, then laid a straight edge going straight out from that center, into the air. I then took the engine and laid it on the firewall, and moved it around until by sighting straight down on the straightedge I saw that the engine propeller hub was centered on it. I then marked the top two holes of the engine.

Grabbing a couple of #8 decking screws, I screwed them into the marked spots, then backed them out and mounted the engine with them. I then installed the cowl, checked that the spinner was properly centered, took the cowl off, and drilled the two bottom holes for the engine, using the mount for a guide for the long 1/4" drill bit.

I then took out the decking screws and drilled holes where they had been. After installing blind nuts, I mounted the engine using 1/4-20 bolts, and again checked that the spinner was centered on the cowl (all this on and off the plane stuff can get tedious. . but it's necessary). After that verification, and checking to see how much I had to move the engine forward, I built a 1/2" thick spacer plate out of aircraft ply, smoothing the edges and contouring it to be just slightly larger than the back to the motor mount. This was then glued in place, and bolted down while the glue cured.

Again the engine was bolted in place, and with the cowl installed the clearance was checked for the spinner back plate. As can be seen from the pictures, it was perfect at 1/16" or so of clearance, and perfectly centered.


Some dimensions to use:

Offset for most engines will be 5/16-3/8". For the DA-150 it was 5/16" to the left of center.

A 1/2" spacer plate spaces the DA out perfectly for this plane. For a little weight shift forward, and more clearance on the cowl, 3/4" is not unsightly.