moses

I attached the landing gear mounting plate last night. I could not find any CF gear that was ready made. I'm going to use the supplied landing gear for now. Perhaps some weight could be saved by adding some lightening holes like the picture below. I wonder how much weight is saved by doing this ?

cu. in.

Since the gear blank was originally a flat plate, weight reduction % can be calculated by subtracting the area of the drilled holes from the area of the undrilled gear and dividing by the area of the undrilled gear.

However, I have a background in machining and have some concern about drill press safety when drilling large 3/4 holes in .125" tempered aluminum. This work should really be done by a trained machinist in a machine shop. In addition, most modelers don't even own a 3/4" dia. drill.

If we don't have any luck with the CF gear route, then I may take a "cut" at it in the near future. My spare time right now is almost nonexistent.

Bruce

cu. in.

Kevin returned my e-mail but indicated that the Ecstasy CF LG won't work. Here is what he said:

Sorry - No. The Ecstasy CF LG is only 3" wide at the fuse. I wouldn't look
right, nor mount properly. Also, the Ecstasy is only 7-1/2 pounds verses
yours at 9. I am sure that it would support it, but I don't think that it
would be a fix long term, though mine is only less than 4 oz. on a postal
scale.
Sorry I couldn't help you out, but I thought that I would offer.
Kevin

Thanks Kevin - I agree.

I had another thought on the landing gear holes suggested by moses. Rather than drill the holes, they could be punched. I will check with a local sheet metal shop next week. I have worked with them before and they are good folks.

Bruce

moses

I got the landing gear mounted tonight. The idea of punching holes in the aluminum gear (as opposed to drilling) makes sense. For some reason I’m thinking the gear would be stronger if the holes are punched rather than drilled (I’m thinking the metal is compressed a bit during the punching operation).

I made up some mounting blocks for the Sullivan tail wheel so it can span the mounting point for the flying wires (tail support). I need to get the holes drilled for the engine mount. I’m not sure of the best way to do this – any suggestions would be appreciated.

Still have to hinge all of the control surfaces. Everything is in place for using Robart hinge points. I even removed the teeth from a few hinge points so I can test fit everything without unduly enlarging the holes.

Once the engine mount is bolted to the firewall I’ll almost be ready to check out the initial balance of the plane.

Moses

Volfy

My Feedback: (23)

You might consider lightening holes on the center section where it contact the fuselage. This is the least stressed area of the gear, as most of the normal load is transfered to the fuse. This leave a large amount of bending moment concentrated at right near the "knees", and that's it. If you reposition your mouting bolts strategically, there should be no compromise in its load handling.

moses

Another update … I decided not to use the Du-Bro 688 mount. It is a very nice soft mount but the Saito 120 does not really need a soft mount - plus it is a bit heavy. So I’ll be using either a Dave Brown or Great Planes engine mount instead. This should save a few ounces.

Going to the LHS in about an hour - they have both mounts in stock. I like all of the suggestions on lightening the landing gear and mounting plate. I’m sticking with the stock configuration for now.

Moses

tsaldivar

My Feedback: (3)

Looks like a slightly modofied Somethin' extra to me!

moses

Careful now … its an AK Models 3D Freedom … and it looks like an airplane. The Somethin’ Extra is made by SIG. As we all know, these are two different (perfectly lovely) companies and two different (perfectly lovely) planes.

Moses

tsaldivar

My Feedback: (3)

Oh yeah, that's right!

moses

Trip to the LHS was a success. I went with the Great Planes engine mount. It came with a nice little template so I mounted it right up. I will have to weigh the thing to see if I saved any weight over the Du-Bro.

I got motivated and I worked out the spinner adapter and reamed out a prop. I got lucky – I was able to use the simple spinner adapter (no counterbore in the prop is required ). All I had to do is cut down the spinner mounting bolt by 10mm – pretty typical for Tru-Turn spinners. So I’m all set on getting the engine and prop mounting. I have to think about the throttle linkage a bit - does not look too difficult.

If I can just get a little more time tonight, I will get the holes drilled for the servos and get them test mounted. This weekend looks like rain. I might just make some headway (since I will probably not be at the flying field).

As for tsaldivar’s comments … I do understand his point. I have no affiliation with AK Models or SIG. I guess AK Models deserves to catch a little flack. I (obviously) don’t have a problem with the 3D Freedom. So far it looks like it’s going to be a really nice plane.

Moses

cu. in.

I thumbed through the July issue of RCM after dinner tonite and found another LG manufacturer on page 39. The company is Tetherite in Webster, TX. They make four gear sizes out of glass-filled nylon and one of them, Model TPP-011, is about the right size for the 3DF. The dimensions are:

Fuse = 4.1" X 2.25"
Height = 6.0"
Spread = 13.5"
Profile = 2.25" X 1"
Weight = 5.0 oz.
Cost = $24.95 + $5.00 shipping (includes axles)

AFAIK, they don't have a Web site and don't take credit cards. I am going to e-mail them tonite and probably purchase one gear. I will also ask if these gears can be painted.

I am still going to check into the hole making situation next week, but this is an easy way to save over 2.5 oz. and anybody can get one without messing with job shops, drawing plans, etc. Still, the gears with holes like moses posted do look cool.

And, BTW moses, thanks for all the great graphics work. It's a big help.

Volfy - I agree. I am thinking about punching three 3/4" holes in the center section as well as various hole sizes in the legs. I also feel that flat gear should have bolts front and rear to handle the bending moment imposed by landing forces. Additional fasteners add a little more weight of course.

Bruce

hardlanding

Hey guys,
I just recieved my 3D Freedom from AKM, and its great to find this thread. My question is.....does anyone think the Saito 1.50 is too much engine for this plane? I have'nt opened the box yet....so also curious if it has pre-shaped leading edges.
Thanks for any opinions guys.
Mike

moses

It looks like the Great Planes engine mount weighs about 5 ounces with the mounting hardware. This saves at least 2 oz over the Du-Bro soft mount.

hardlanding - unfortunately the leading edges are not pre shaped. In framing up the wings you glue the ribs to a thin balsa sheet (false leading edge). Once the wings are sheeted, you glue on the end caps (these have a profile of the airfoil) and the leading edge block. Then you shape this sandwich of leading edge blocks to match the end caps. I used a Great Planes power plane to remove most of the excess balsa (worked quite well I might add). Then it’s just a matter of sanding with a long sanding bar. The balsa included with the kit is very nice quality and shapes pretty easily.

In retrospect I was thinking that I should have gotten Saito 150. The Saito 120, 150 and 180 are very similar in weight.

Saito 120 = 820g (28.9 oz) w/muffler
Saito 150 = 890g (31.4 oz) w/muffler
Saito 180 = 880g (31.0 oz) w/muffler

Depending on the balance (e.g. if the plane is a bit tail heavy), the 150 could be a better choice over the 120. I doubt the extra power would be a problem. If you have unlimited cash - a YS-140FZ would probably be a amazing in this plane (very expensive though - almost $600).

By the way, you can sometimes get a discount on Saito Engines from places like Chief Aircraft and Quantum. You just need a bit of luck on the timing of the specials. This month Chief has the Saito 120 on special for $300 shipped (not too bad). I bought mine from Chief last month but I paid a bit more - oh well. Next month you may be able to get the 150 on special - perhaps in the $340 range.

Moses

hardlanding

Hey thanks for the info Moses. I think I will probably go with the Saito 1.50, I dont thing the little lady would would be too nice to me if I went for the more expensive YS. It was already extremely difficult to make her understand why I couldnt use one of my other engines for this plane (.40 - .90 2-strokes). Plus then theres the new radio I will be getting and the hi-torque servos. $$$$$!!! Women....can't live with 'em.....the end.
You mentioned you have the GreatPlanes power plane. I was thinking about ordering one of those myself.....I love my power hinge slotter they make.
Thanks again,
Mike

moses

Yep, the power plane is a very nice. Using the power plane I had the wing panels looking pretty close within about 15 minutes. It all depends on how close you want to go before you switch to the sanding bar.

Honestly though, the balsa in this kit carves and sands very nicely. Any type of hand plane or even a sharp hobby knife can be used to remove excess balsa without a problem.

The Saito 150 seems like a fine choice to me. There are quite a few engines that look like they might work well with this plane. If the plane comes out nose heavy, perhaps a lighter (and less expensive) two stroke would be better, for example:

SuperTigre G-90 (~$150 - 27oz w/muffler)
O.S. .91 FX (~$200 - 24.3oz w/Muffler)
O.S. 1.08 FSR (~$250 - (26.5 oz w/Muffler - I think)

I hope to have some balancing done this weekend.

Moses

cu. in.

Here is the reply to my Tetherite TPP-011 inquiry:

Hi Bruce;
Web site is "in the mill". And we are setting up credit card sales via
"PayPal". For now, if you send your mailing address - we will ship your order
with an invoice for payment. If you would just like to send an order with
check or M/O, we do it that way.
Glass-filled nylon paints very well. Automotive acrylic enamels, rustoleum,
Krylon and the water based urethanes all work well.
Thanks for your inquiry.
Best regards.

On Fri, 11 Oct 2002 02:32:34 +0000 [email protected] wrote:

> I would like to purchase one TPP-011 landing
> gear. I saw your ad in the July
> RCM where the price is $24.95 plus $5.00
> shipping.
>
> Do you folks have a web site?
>
> Do you accept credit cards?
>
> Can these nylon/glass gears be painted?
>
> Thank you,
>
> Bruce Sheldon
>

I will go ahead and purchase one and report back. Will also check on the punched aluminum gear.

Bruce

moses

Status update - the canopy is on - I used little screws. I'm going to paint it black from the inside but everything looks pretty nice inside. I glued some tiny pieces of light ply under the front two screws for extra strength. I might add a few more screws but it seems like the thing is on there pretty solid.

By the way, the canopy comes with guidelines molded right in – I just followed them and it fit nicely. I just did some very minor trimming from that point. The two screws in the front do a nice job of forcing the canopy to follow the contour of the fuse.

I covered the hatch to see what it looks like. It came out OK - but it is not perfect. I had to use some light filler to clean things up - the finish could have been better. This part was the reason I came up with the sheeting technique posted above.

I did some very rough balancing with the configuration you see:

- control surfaces not hinged - held on with masking tape,
- I just rested the ailerons on the trailing edge of the wing,
- I threw a few servos in the tail,
- I did the best I could in simulating the weight of the push rods and control horns on the tail group ...

And .... it balanced just fine (about 4" behind the leading edge with the battery under the canopy). I doubt that I will need to add any weight – just moving the battery around seems to do the trick. This is a large plane and the battery could very easily go under to fuel tank or the canopy or virtually anywhere in between.

By the way, that composite gear sounds very nice. I may have to get me a set.

Moses

moses

Here is a side view

moses

Here is the tail group - that rudder looks pretty big to me.

moses

A better view of the canopy

moses

Here is the front view of the canopy. You can see that sheeting went on without a seam - no filler needed.

moses

Here is a view of the other side.

moses

Here is a view of the underside of the wings - I cut the holes in the sheeting and drilled the holes for the aileron servo mounting screws. Still have to do the finish sanding on the wings. A tiny bit of filler will be needed where the sheeting joins the leading edge blocks.

moses

Here is an old pic showing the balsa blocks that I glued to the trailing edge of the wings - so the Robart hinge points have something to grip. I did the same thing on the ailerons.

hardlanding

Does anyone have any concerns about the structural integrity of the tail surfaces on this kit? I got a good bit built this weekend, and looking at the grain of the balsa, I just have a fear of the rudder snapping in half vertically during a high force maneuver. Has anyone considered sheeting these surfaces? I know the monokote will offer up some strength, maybe that will be enough. Maybe I'm just being overly cautious. Also, did anyone beside myself notice the contradiction between the plans and manual about which side the dual servos for the tail surfaces goes on? Just curious.
Mike