rogerswin

My Feedback: (2)

It's taken me about two years to acquire all the components for Hostetler's "Skymaster". I will finally start construction this weekend! I'm using "Precision Cut Kits" wood kit. I've changed my mind many times on color schemes, engines, 2-receivers or one, backup battery system, type of batteries, etc. I'm very thankful for this site. I read every post I could find on whatever decision I was working on at the time. The last decision was what type of batteries to use, and how many. Several of your comments (all of them!) turned me away from the sealed lead/acid. I'll be using the "DPSI RV Twin" system with two LiPo batteries for the two receivers, and another separate one for each of the two engine ignition modules. I'll be using a Fuji 50 for the front engine and a Fuji 43 for the rear.

It will be built as the "336" fixed gear version with brakes on the main wheels. It will have running lights with strobes, and landing lights activated by the flap circuit. The color scheme will be the same as my avatar. I'll take pictures as I proceed and if anyone's interested, I'll post them here. I'm a slow builder, so this will take awhile!

Roger

saramos

This sounds like a great project and I would enjoy following your progress. I inherited an old Royal Skymaster kit that my father started many years ago. I am sure that there will be much that I can learn from your build!

Scott

GRANT ED

I'd like to see some pics. My KM 336 is almost finished. I consider the 336 to be the perfect twin model I'm surprised more people don't have them.

FlyingTyger

My Feedback: (2)

A flying buddy built and flew one last year. Flies wonderful. I think his weighed 44 lbs with 2 G-45 engines. Finished it as a Navy O-2, but with fixed gear. Good luck with your project.

sebo

Not exactly giant scale but I like them too! The picture is a Royal kit.
Royal is out of business but I liked thier kits.
Hostetler's plans are great too. I'm finishing up his Cessna 150 and getting ready to start his Lancair. I used the same cutter as you.

eagledancer

i too am thinking of building this plane, i already have the plans, it looks like a straight forward build. i will watch this thread with intrest

rogerswin

My Feedback: (2)

Go to my gallery for the first of a series of pictures I will be posting as the construction on this Skymaster progresses. I will try to answer any questions about the plans, etc. So far the construction is pretty straight forward. I've found a few mismatches between the plans and the kit cutter, but nothing that couldn't be worked around. "Precision Cut Kits" supplies a great wood kit. It comes in a double decker box with all the pieces labeled to match Hostetler's plans.

Roger

why_fly_high

My Feedback: (19)

Anyone interested in an interesting 337 project should check this out.

http://web.nps.navy.mil/%7Ecirpas/

Dan

rogerswin

My Feedback: (2)

Dual receiver system,

I set up the dual receiver/battery, "DPSI Twin", on the bench to see how it operates (see photo in my gallery). This unit works beautifully! It is a TRUE redundancy system. ALL servos are controlled by receiver No. 1 until something goes wrong, such as a loss of power or signal from that receiver, etc. It will then switch ALL servo control to receiver No. 2. It also handles redundant batteries. The only drawback is that it cost about $1000.00! To me it is worth it. I'm going to have a lot more than that in the construction of my model. If this unit could someday prevent a crash - I'm all for it.

Roger

rogerswin

My Feedback: (2)

Moving right along

This last weekend I was able to temporarily install both engines and the landing gear. I will be installing both throttle servos, the kill switch servo, the brakes servo and the nose wheel steering servo next weekend (I hope!). All flying surface servos will be in the center section of the wing/fuselage. I've included up-to-date photos in my gallery.

Roger

rogerswin

My Feedback: (2)

Well, it's growing

I've posted a few more construction pictures of this model in my gallery. These are just the "main bones" without the fine work. It has taken me longer than I anticipated to get to this point because I'm totally changing the way the control surfaces are operated. There will be no visible control horns, push rods, etc. It is being set up as an enclosed pull-pull cable/pulley system. No bell cranks or push/pull rods (except for the chokes and throttles). You can't see too much from the photos, but hopefully the idea is evident. The next step is to install all the little formers and some sheathing.

Roger

sebo

How do you keep the cable from slipping on the pully? Why are there connectors both inside and outside (the actual aileron) on the control rod? I am totally confused about this setup but I think that (if I could understand it) I may attempt to use this application in one of my future aircraft. How about a few photos with magic marker lines showing what is really going on. Or maybe, a drawing of the principle of how this setup works. Thanks, Ron

rogerswin

My Feedback: (2)

Hi Ron,

I was afraid it would appear confusing just by seeing the photos. I've made additional photos of the pieces and some sketches. these have been put into my gallery.

I've also made a design change that does not show up on all my photos. If you look at the photo showing the right wing tip supported on the empty 5-gal. water bottle, you'll see my final solution. Note the aileron: I've gone to a full-length split light-weight wood dowel on the aileron leading edge for the ribs and sheathing to attach to. Now look at the flap location. What that is is a trailing edge with a fiberglass form to match the split dowel leading edge of the flap or aileron. This allows a real nice meeting of these two halves (see new photos). The fiberglass is formed over a section of aluminum tubing. In my case, the aluminum tubing was 1.250" O.D. and I used a 1.250" wood dowel, cut down the center. Buying 1/2-round material at a wood trim shop will work.

The material such as the brass tubing and brass flat stock can be bought at most any hobby shop. Look for the rack that has all different shapes of small aluminum and brass.

With this method, the servos can still be mounted in the wing at the control pulley, or by using Proctor's pulleys the Kevlar cable can be routed back through the wing to the first rib bay if wanted. A flush access hatch can be installed in the wing bottom wherever the servo is. After the servo is mounted, take up all slack in the cable and attach similar to the aileron pulley, or use whatever attachments you want. Use short servo arms to match the pulley movement and adjust with the transmitter. The flap setup is similar except a stop is installed for excess "up" movement. With a little thought, routing for the elevator and rudder is similar. I plan on using two servos each (two in each wing) for aileron and flap control.

To prevent wearing of the Kevlar cable at any point where it might touch something, use Gold-N-Rod. Use the yellow piece inside the red piece as usual, but run the Kevlar cable continuously through the hole in the inner yellow piece first. When everything is located where it should be - glue the Kevlar cable to both ends of the yellow inner piece where it comes out (Zap Kicker helps here). Also, glue the red outer piece to the airplane structure as normal. This way, when the Kevlar cable is moved, the inner yellow piece moves and removes all friction from wearing the Kevlar cable (I learned this trick with the Kevlar cable from a contributor here at RC Universe - I forgot who it was, but they get the credit).

Roger

sebo

Thanks! I read and understand completely. The photo documentation was done superbly.
This is definately worth doing. Thanks a million for the photos and instructions. Ron

eagledancer

my understanding is when you add a spot of glue on kevlar cable such as at a knot it will then break at that point
correct me if i am wrong

rogerswin

My Feedback: (2)

Eagledancer (Kevlar cable and glued knot),

All I can say is that I've pulled and yanked and tried everything to see if the cable would break at the pulley, with no success. It might be because the knot in my application is trying to be pulled through a hole rather than the strain a knot might have in the middle of the line somewhere. Also, I have one wrap around the pulley before it goes through the side hole. This would take a lot of strain off the knot.

Roger