Hey,

I'm building a TF spit and reached the point where decision about the retracts must be made.
I'm going with the recommended Robart 605HD (the retract of choice for this kit according to TF). Can Robostrusts be used with this kit ? the problems I see are (a) the need to bend the strut wire forward (how to accomplish this with the robostruts) , and (b) the the robostrut being longer than the length fo the strut wire in the plans (so there will be a need to cut down another rib to accomodate the wheel wells).
Does anyone have any experience with this combo ? any tips ?
Thanks,
Biton

I would go with the Century Jets or at least upgrade to a better Robart. The CJ may seem a little spendy but will save many a headache later. To move the strut forward, just shim the back of the retract unit.
[link]http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXA802&P=0[/link]

I've installed Robostruts in my TF spit. In the installation of Robostruts, you do cut them to length, After cutting them to length, you add the adapter bushing to the top of the strut which will accept the wire stud mounted in the retracts. There are two methods for securing the adapters, solder or JB Weld. I would recommend the JB Weld. I tried the solder aproach and it damaged the plastic spring retainer plug.

After cutting the struts to length, you will not need to cut into more ribs. However, in order to get the wheels and struts to fully retract, I ended up completely cutting out the section of the rib where it passes through the wheel well. I also enclosed the wheel well for looks and added strength. Check out the TF spitfire build thread authored by Tubig. This, and much more is discussed. You can also take a look at my gallery where I have posted some photos of my build.

I did not bend the wire forward. The angle of the retracts are set with the positioning of the retract mounting rails. These I installed according to plans with no modifications. As it is, the wheels come right up to the main spar, and adding more forward sweep would cause the wheels to retract into the spar.

Scott

Saramos,

Could you elaborate a bit on the techniques of attaching the adapter wire to the robostrut ?
Thanks,
Biton

What I did was to use the wire struts that came with the robart retracts. I mounted them into the retracts and cut them to the length suggested in the Robostrut installation instructions (about 1/2" exposed stub).
Next, I cut the robostrut to lenght (about 4 7/16" from the center of the hub, or 4 5/8" total length).
The robostruts come with an adapter bushing which will fit inside the end of the Robostrut and will slip over the wire stud mounted in the retract. Mix up some JB Weld and apply it to the outside of the bushing, then insert the bushing into the Robostrut until it fits flush with the end of the strut, and let cure.
Drill two holes through the strut and bushing, and thread them for the set screws provided. Insert the strut over the wire stub with the strut hinge pointed foreward, attach the wheels (I used Robart 3 1/2" wheels), mount the retracts, and start making adjustments for your alignment. On my installation, the wheel just cleared the main spar and the rib just outside the wheel well. Once I made all my adjustments, I removed one set screw and drilled a small indent into the wire stub, replaced the setscrew and repeated on the second set screw. This is to prevent the strut from rotating during takeoffs, landings and ground operations.

Hope this helps,

Scott

Biton,
I was thinking about my installation. If I recall correctly, I replaced the setscrews that came with my struts with longer setscrews. Long enough that when fully inserted, they still protrude a small amount (1/64 - 1/32") above the surface of the strut. This will help prevent the robostrut/bushing from comming loose or rotating.

Scott

Scott,

Thanks a lot for the info. It sure clears up th issue.
Did you use the Robart 605 retracts or other brand ?
Biton

Yes, I used the 605s.

Scott

Scott, nice build![sm=thumbup.gif]

can you give me more details about the instrument panel? i like it!!!!

thnx

Thanks,

The panel is made of several layers. The back panel and the flight instrument panel were made from 1/32 balsa and thin styrene. I used sharpened brass tubes of various diameters to punch holes for the intstruments. Then I added a layer of clear plastic between the styrene and the balsa for the lenses of the instruments. I scanned the printed instrument sheet from an old Royal products cockpit kit and used photos of the actual cockpit as the basis of graphics I created using Corel Draw. I printed out the instrument faces, cut them out and glued them into position on the back side of the balsa. For the raised bezel faces, I cut out more styrene. For the bezel rings, I took small guage wire, wraped it around the proper sized brass tubing and cut a circle out and glued them on. The switches are small pieces cut from plastic toothpicks. The bolt heads are drops of alphatic resin. Then all was painted with the appopriate colors. It took two tries, but I had a lot of fun doing it.

Scott

thanks for the info Scott,

would it be possible to have a copy of your scanned files? I have a Hacker Spit and I'd love to try and replicate the look you have created

Vasek

Here's a jpeg from the cdr file I used.

Scott

[sm=thumbup.gif] thanks Scott