ww2birds

My Feedback: (14)

Thanks guys for the feedback, and thanks Tommy for the flying tips. I've been "practicing" on a friend's Kingcat with a JetCat Titan, so I know what you mean about more vertical than one is immediately comfortable with :-)

EddieP asked about the Wren 54SS install. When I ordered the kit, Bruce told me he did not have a specific Wren mount, but had one that he thought would work. It did...unfortunately, I have no idea which one that was! Bruce probably does...

It was a really easy task to get it to work with the SS. First had to spread the "wings" slightly (maybe 1/4") to get the right spacing, used my woodworking vise and calibrated eyeball. Then drilled a 1" hole for the glowplug which sits at 2 O'Clock, and finally a little Dremeling to relieve some metal to clear the thick end of the thermocouple. I think it's pretty clear from the pics... Took an hour or two at most. I presume this is not so different than one would have do to on any of the turbine mounts.

Dave

MECHIE TECH

Hey guys,

Anyone thought about, or even done, the R54 wing as a two piece for easier transportation? or would it be more trouble than it's worth?
Great thread BTW, excellent job on the Panther like colour scheme ww2birds.

Best regards,

M.T. [sm=thumbup.gif]

TommyWatson

My Feedback: (1)

I think you would need to make the fuse in two halves as well. That is the hardest part to get into my car. You would have to do some carefull design work to make sure it was strong enough.

Regards

ww2birds

My Feedback: (14)

Thanks, MT.

If anyone does a multipart wing, I'd suggest a break just beyond the gear with plug ins with a wing tube .. this is how a lot of warbirds are, and it's a good compromise between spacing saving and easy transportation. I guess that would be a three-piece .. but in the end easier than making a removable center joint..

Dave

(edited for typo)

bobparks2

My Feedback: (1)

I agree. A 3 piece, with the split right at the outboard end of the flaps would work well. I just did a REALLY rough estimate of the joiner loads, and it looks like about 1000 inch-pounds bending moment is about right. A 7/8" diameter, .049 wall 6061-t6 tube would be appropriate (TNT WT-370 with matching socket).

I know that a graphite tube could be lighter (and maybe smaller), but its very hard to tell just how strong the various tubes are, since so much depends on the way they are made, and what kind of fiber is in them.

The joiner tube could be done so its only one rib bay long on each side of the joint, but you need to be careful to have strong enough rib doublers and shear webs, and good glue joints to make it work. If you had the joiner go two rib bays on each side, then its a lot less critical.

I would just add doublers to the front and aft faces of the spar so the spar width was about an inch, then have shear webs that go full height of the wing, bond to the spars as well as to the full length of the phenolic socket. For the short joiner, a 3/32" thick doubler on the rib (chordwise dimension of 3") plus an additional, mainly vertical grain, 3/16" doubler that fits the tube and the spar and between the shear webs, top and bottom, with good bonds to all of them. 3/32" ply wood shear webs front and back.

Note, I tend to be VERY conservative with wing joiner sizing. The above tube is for a 30 G maneuver, and has some margin on top of that. They plywood part sizes are based on a ducted fan airplane I did with similar performance to the R54.

As for the fuselage, a removable tail boom would be tough to do. OTOH, it would not be that hard to make the tail surfaces removable. (but the weight is all added at the wrong end of the airplane!).

Bob

MECHIE TECH

Excellent write up Bob,
thanks for your thoughts guy's. Just an idea I had whilst killing time NOT building, i'm away from home just now. I've just started to build an R54 for an MW54 turbine, but I won't be messing with Bruce's already well proven wing design, just need to be careful when loading up the car for the field [sm=lol.gif]

Regards,

M.T.

Ed

And regarding the Kavan brake also ................... Do you use a seperate battery pack to activate it, or the ECU pack ? Also, is it controlled by a servo, or a special switch ?

> Jim

bobparks2

My Feedback: (1)

There is a post I did in this thread long ago about that, but I use an old 2 cell Lipoly battery, and a brush motor type ESC to get proportional braking. You need to program the ESC to have fixed "throttle" range.

The brake pulls about one Amp, so you could use the main radio battery pack, or even the ECU battery for it. I needed nose weight anyway, and I had the LiPoly pack, so I used it. The only problem is remembering to plug it in before the first flight of the day and to unplug it at the end of the day.

Bob

Boomerang1

Hi Jim, I use the Kavan brake on my model. I run it off the 6 cell ECU battery & it works fine. I've wired it through my ECU switch so it can only work when the ECU is on. It's activated by a micro switch on the elevator servo, full down operates the brake. The brake is heavy, offsets the wheel a long way & it will not stop on a dime from high speed but is great for taxiing & reducing the landing roll. You do not really need proportional control on the brake, it's not that powerfull. I only have it fitted to the nosewheel.

In Australia you do not have to fit a brake unless the model rolls with the engine at idle. My model does not roll but I'm still glad I fitted the brake, on a smaller model I would not bother. In the US I believe you must fit a brake to turbine models regardless. - John.

Ed

I know that pleated paper fuel filters have been talked about in this thread. Are they available in different sizes, and where can they be purchased ?

And also ......... Can black glow fuel bungs be used in tanks using kerosene, or must they be the brown gasoline type ?

> Jim

Boomerang1

Jim, you have to use the brown bungs suitable for gasoline. The tubing also must be tygon (the yellow stuff) or neoprene.

http://www.intairco.net/default.asp?...cat=182&id=799
Is the fuel pump I use, it seems to be holding up well.

http://www.intairco.net/default.asp?...cat=170&id=492
I noticed your post regarding header tanks, I have used one of these header tanks which you can empty
completely which I believe you cannot do with the BVM units. Mine has festo fittings but the word is they
are pressure fittings & not ideal for the suction side of the fuel pump. With the tygon tube you would be
better off with barbed fittings anyway.

I only use a pleated paper filter on my field box pump. The local auto accesories shop has them in lots of
sizes but the lawn mower shop has the really small ones along with tygon tube. - John.

BruceTharpe

My Feedback: (1)

Jim, this link will take you to my post on the fuel system I used in my latest R54. It uses a pleated paper filter as a clunk in the header tank:

http://www.rcuniverse.com/forum/fb.asp?m=5674381

The filter itself is a pretty standard item, used in US auto carburetors for many years. They do come in short and long versions; this is the short one. Unfortunately, you do have to do some custom machine work to add a barb for the fuel line.

John is right about the bung. Do not use the black one for glow fuel. Use the brown one for gas - DuBro marks this with a "0" molded right on the bung.

Ed

Hi Bruce, it's good to hear from "The Man" himself. This is Jim Lynch in Tucson, and we use to talk at length at Sam's Town in Las Vegas, back when they held the QSAA event there. In fact, I'm still flying the Vortex that you sold me over 10 years ago, and it's on it 2nd ST .90. I don't own a turbine yet, but I'm working on it. I read the complete thread on your very impressive Reaction, and I'm torn between putting a Turbine in a Reaction, or on the back end of another Vortex, such as they have been doing with Enforcers. As an X engineer, I like to build and stay innovative. And so .............. I'm collecting as much turbine information as I can, in order to plan for the future.

OK, so now, how does a UAT differ from a 16 - 24 oz header tank, and is it just as effective in eliminating air bubbles ?

Thanks > Jim

BruceTharpe

My Feedback: (1)

Hey Jim, you're touching on a subject with a lot of opinions, so all I can offer are mine...

In a nutshell, a simple fuel system installation will consist of a main tank and a header tank. The main tank, of course, holds the bulk of your fuel, and typically uses a normal weighted clunk. The header tank is usually smaller, and its main task is to provide bubble-free fuel to the pump. The UAT is a header tank, it holds 4 oz. of fuel, and it uses a fiberous sack that the fuel must pass through to get to the pump. The sack retains pure, bubble-free fuel even if some air makes its way into the UAT. It's supposed to work even with as little as 1 oz. of fuel in the UAT, but most modelers plan their flight time so they don't actually use the fuel in a UAT. Normally you end up with just a small amount of air (outside the sack) after each flight. It works great, I used one on the original R54, and it is even shown on the R54 plans.

I wanted more fuel capacity, so I made the header tank bigger on my second R54. Instead of a UAT, I used a DuBro 16 oz. tank. The big difference here is that I wanted to be able to use some of the fuel in my header. But I still needed to avoid bubbles getting to the pump. So instead of a sack, I made up a pleated paper clunk to do the job. I didn't invent it, but read about it several years ago on the JPO website (I believe). This system also works. It is not better or worse than using a UAT. They both work.

There are many variations that will also work. Some guys use a single main tank (no header) with a pleater paper filter clunk. Some use the pleated paper filter in a small header tank, but insted of making it a clunk, they fix it so it's stationary in the center of the tank. Like the sack in the UAT, the pleated paper filter will not suck bubbles even if much of it is exposed to air.

Woketman

My Feedback: (6)

I use a large main tank with a large clunk with very flexible Tygon (to allow the clunk to follow the fuel as well as possible). For the header, I usually use a 20 or 24 ounce tank with a weighted pleated paper clunk to also follow the fuel with real thin walled Tygon (flexible). It works REALLY well. Years ago, I took the original Isobar up high and intentionally ran it dry to see how much fuel would be left. There was a few (literally JUST a few) drops left in the header and literally residue in the main.

highhorse

My Feedback: (2)

Hi Bruce and Woket, I recently bought a used R54 seen here previously and origninally built in Houston (?) by Barry (?) u2fast (?). It seems to have been VERY well built and I'm happy to own it. I'm in the process of tweaking it a bit and installing a Wren SS.

The fuel tank seems pitiful tho, so I'm gonna either install one of Gary's 72oz kevlars, a custom built 90oz kevlar, or perhaps just a 32 oz header to supplement the 50oz Dubro currently installed.

(Gary, answer your email dude!) :-)

Here's my question, guys: Where can I get one of these fabled/awesome paper pleated clunks?? Is there a pic available? Pretty please?

Thanks to ALL who post here so that the rest of us can learn from your efforts !!

Don Ray.

causeitflies

Here are a couple pics that I used as a guide to do mine. I believe these photos came from Mark (Wocketman) Pokrywka & Steve Ellzey.

highhorse

My Feedback: (2)

a 27 minute response, pics and all !! THANKYOU!!

Ya gotta love RCU, man. These people are GREAT!

u2fast

My Feedback: (37)

high horse, i hope you enjoy my old r54. i had hundreds of flights on her before selling her to alex. i had a second kit sitting around and i wanted to build a second. i knew if i kept the first around, i would never get around to building the second. so i sold her to alex. she is a solid flyer, hope to see her around again. barry

Ed

What is that rough looking tubing made of, and is it soldered to the filter ?

> Jim

causeitflies

The example shown uses JB Weld to hold the parts together. The tube is just various diameters of brass tubing soldered together for the proper fit into the filter. You can also solder the tubing to the filter. I have done it bothe ways and it works perfectly. It can be used as a clunk or in the center position in the hopper tank.

Ed

OK Mark thanks, and what are you using for a weight, and to plug the hole at the far end ?

> Jim

causeitflies

In the photos above they used lead shot and JB Weld for the shaped weight. The end of the filter is closed. I haven't used this in the clunk configuration yet. I have it in the geometric center of small 4oz. hopper tanks and have used the longer filter in a 10oz. pre-hopper tank.

highhorse

My Feedback: (2)

Hi Barry, I will do my best to take care of your baby !

I've been doing a bit of carving, grinding and cutting to put the SS into it. I'm mounting it fwd of the position the P60 was in and have intruded into the boat-tail with the starter. I've also re-plumbed some of the air system since I was moving things around to mount the Wren accesories. I am VERY impressed with the meticulous attention to detail in your original install, but have made a new aft chassis anyway for the new components. I'm keeping your original front chassis since nothing there is changing.

Hopefully I'll be in the air with it in Feb. I'll keep you posted.

Woketman

My Feedback: (6)

The photos above were taken after I built one put together with JB Weld (as correctly stated above). I have considered soldering (as some have apparently successfully done) but I was always concerned that it would weaken the black glue that attaches the pleated paper to the end caps. Mark is correct about the shaped end. It is just lead shot mixed with more JB Weld slapped on the end. Then, after curing, I just grind it down to a bullet-nose shape on the grinding wheel to allow the most efficient shape for getting low and into a tank corner.

This REALLY works great guys! If I was putting this into a smaller model, where I might not be able to fit something like a 24 oz. header, I would not hesitate to use the geometrically centered header approach as mentioned by Mark above. I have not tried that, but it should work very well too.