Tuggs

Hi Dirk!

Impressive Model! Looks fantastic... Good motivation to finally get started on mine. I already sanded some seams and will get started on the gear door and servo installation tomorrow. Pics will follow.

By the way ... where did you get the windscreen wipers?

Regards

-T

husafreak

My Feedback: (3)

Man I wish I had some of that stuff! He didn't keep much and the few pics he had are cross country at my Mom's. Great project though!

dirkcim

Graupner Heli scale set.
I stil got one :-)

Tuggs

Nice one Dirk Let me know if you would like to sell the scale kit. I'd take it.

Alright...

On Saturday afternoon I finally had time to get the build started. Thanks to the high level of prefabrication, every assembly unit can be finished within a couple of hours. Over the years I've buit quite some so called ARFjets (except FEJ) and I mean it when Isay that the top noch quality of this kit keeps impressing me. But enough with the hymns of praise. As the build goes you may realize that I am trying to keep things simple and functional for daily use.I would consider myself an average builder only (you will see that soon enough). What Iam really looking forward is to give this bird its paintjob and some decent weathering.

<u>Tail section</u>

First thing I did was to make up my mind about the tail section. There are 4 blind nuts installed into the formers already, so the only thing left to do is to decide whether to fix the tail in place or keep it removable. In regards to easier transportation, I decided to open the vent in the rear part of the fuselage, because from there it is easy to reach all screws quite hassle-free. Once that was finished, I trial fitted the tail on the fuselage. Good fit. Later on, I am going to convert the "vents" on both sides into working hatches.

Tuggs

Next I moved on to the servo installation for the rudder and elevators. No surprises here and pretty much straight forward as expected. With those unique servo mounts, the only thing you have to do is to measure the exact position of the servo arm. Not a very challenging task, but still it is important to be precise with it.

Pay attention during the rudder servo installation. the plywood former inside the fin provides a cutout for the servo arm. Looking from the rear, the rudder servo arm has to exit the fuse on the right side. Otherwise there is not enough space for the servo arm to rotate. I had to figure that out the hard way. I have to get longer servo arms this week, as the ones in place a are a bit too short. Also, some more trimming on the cut-outs is necessary. The control horns will be done all at once with flaps and ailerons later on.

Tuggs

I thought it was good time to temporarily remove the fuel tank. Once I am going to install the bifurcated tailpipe, I have to remove it anways because otherwise there is no way to fit it. I am still considering the option of 2x2 litre tanks mounted in the turbine bellys because Iam going for a single turbine configuration.

Have a look at the mount for the huge fuel tank. I think it is nicely done. With the tank removed, the huge fuselage is looking very empty!But I somehow have the feeling that this is going to change soon enough.

Tuggs

What Idid next is something that I really don't enjoy much. Gear door installation.

But before I share those building steps with you guys, some more pictures of the wing first. First, I trial fitted one landing gear to check the looks. The gear door well provides more than enough space for pneumatic cylinders or servos, and some nice detailing on the doors and the well itself. Ihope I am going to receive my scale documentation on the Scorpion. The gear door is readily cut and you have to split it between the main gear door and the small cover for the leg.

Regarding the construction of the landing gear units we spoke about ealier. I believe the idea behind the pin method over the clamping may be a predetermined breaking point. The pin may bend or crack without destroying the leg or retract unit. With the clamping method, both could be heavily damaged in case of a (crash) landing. Only my idea, I can be wrong though.

Tuggs

Onto the main gear doors. I really like hinging gear doors with robart pin hinges. Since the Scorpion main gear doors have the size of barn doors, a solid joint and leverage is imperative. To keep the doors adjustable ANDremovable I use the robart sleeves for the hinges.

It took some patience and fiddling to get the fit right. Furthermore, it is necessary to balance the height of the pins on the door towards the pin with the sleeve in the wing.I enlarged the cutouts for the hinges just as much so the gear door can open up to about 85 degrees. This will be sufficient for secure gear operation and I think it does look better.

At this point I'd like to mention that the gear doors are layered with carbon - very beefy.

Tuggs

Pictures of the finished main gear doors (done for both wings). Almost gap-free and smooth operation. I am happy with the result so far. My plan is to install the servos in the wings and all pushrods tonight. Up next will be final landing gear installation in the wings. I am still unsure whether to move the front leg in the "scale"position or leave it where it is.

BTW: I decided on the powerplant: Behotec JB180 (newest generation with internal sensors and kerostarter)

Tuggs

Yesterday I received my scale documentation and I already ordered the paint for the 437FIS scheme. I'll post pictures of yesterday's building progress later on tonight asI forgot my camera at home.

Tuggs

I got some more work done on the scorpion during the last couple of days.

Here are some pictures about the gear door that covers the oleo leg. I use basic plastic hinges for the door.A simple pushrod will connect the door to the leg. I'll do that once Iinstall the servos for the main gear doors in the wing.I will also cover the inside of the doors with thin epoxy plates and add some nice detailing.

Tuggs

Meanwhile I fitted the cockpit. There is only little work to do and the tub sits firmly in the fuselage. If you're going to use the big fuel tank there will be some trimming necessary, but I still believe that I am going to use two seperate fuel tanks below the wing.

I am really looking forward to add some life to the cockpit. 1/6 scale pilots will fit nicely.

Tuggs

The next steps are pretty unspectacular, and I hope that I do not bore everyone reading this thread. Again, it requires some attention to cutout the opening for the aileron servos. As I mentioned previously, the servo could likewise be mounted through the wingtip with long screwdrivers, but I think it is impractical since it is literally impossible to check and maintenance the servo quickly, if necessary. Some measuring, double-checking and 4 cuts with a sharp knife and voil&agrave;, the cutout is made (for both wings, of course). I can pusblish the measurements if someone is interested.

As you can see in the pictures,I use carbon pushrods for the ailerons. I use hysol to glue the 3mm threaded alloy heads to the rods (of course the rods are cut to the right length first). Before hysol the horns into the ailerons, Icheck for correct movement and !pretty important, check for the plywood supply plates in the elevators. I do that by drilling small holes into the hidden backside of the aileron.

Tuggs

Servo horns for rudders and elevators are also finished and glued with hysol. Tonight I am going to the final install of the aileron servos, rudder and flaps. After that is done the elevator will be glued to the tail. If its not midnight until then, I think I'll do the wiring for the servos and up next will be the retract install (slight change of plans)

Factorypilot

Great model!  Keep the pics coming!

Tuggs

Will do - thanks for the feedback.

Tuggs

The elevator is now glued on the tail section. I roughened both surfaces and used hysol to put it together.Of course I double checked the holes for servo wires and thanks to the molding on the tail, there is no alignment work necessary for putting the two parts together. Excessive epoxy has been wiped away and as you can see on the pics, the fit is perfect.I'll use some filler for the marginal gap on top. The hysol cured overnight and today Iam going to do the final servo installation in the tail.

Tuggs

Okay. Iknow that this is not overly exciting, but I finished the ailerons!Fitted the servos, locktit'ed the screws and checked movement with a servo tester. I only need to put the covers back in place. Both ailerons are off the list now. Unfortunately I didn't get started on the flaps last night, simply because my wife showed little tolernace for using the dremel after 11 pm last night.

Tuggs

Elevators &amp;Rudder are hinged and wired.First unit of the plane completed and ready for paint job!Woohoo!Pics tomorrow, the weekend has been busy with flying!

k_sonn

My Feedback: (32)

Nice project.  Subscribed.</p>

</p>

Kirk</p>

Tuggs

ThanksKirk!


Okay, back to the build. I got quite some work done and again, I would like to share my excitement here. The tail section is complete as I mentioned before. I have yet to cover the pushrods with shrink tube and solder my servo wire connections (green mpx connectors). But I'll do that once i have the position for the receiver (I dont like too long servo wires). Since I am painting the whole airframe I still have the opportunity to remove some epoxy leftovers and little scratches / seams on the surface. Futaba 9156Servos are used on Elevators and Rudder.

Please bear with me during these pretty boring building steps, but Iwant to keep the whole process documented. I promise it'll get more exicting soon.

Tuggs

Flaps. Pretty much the same procedure as with the ailerons, except that it is much easier to position the pushrod for the linkage. You probably noticed that I opened up the slots for the pushrods quite generously. As you can see in the picture, I'll use a kneeling linkage for the flaps which leaves the servo unstressed in neutral position. I thought this might be clever since the flaps are quite large. I also made some plywood rests for the aileron covers and secured them with 5 minute epoxy. Also, I soldered the extensions for the aileron servo wiring which adds another 5%progress on the wings.Pretty neat, eh?

After work I am going to finish the flaps on both wings and hope to get started on final main gear install.

Tuggs

Main gears are installed now. Pretty straight forward work and again not overly exciting. As I don't like fiddling around with drive-in nuts from below the retract support I made small plates out of plywood and epoxied the drive in nuts onto them. Once drilled, I just pushed and secured the plates below the retract support and the units can be mounted.

Before I did that, I greased the retract units to make them operate smoother. I started using this special grease from a german retract manufacturer a while ago with good results. I also prepared the root rib for BVM EZAir connectors which I use often to spare me from connection air lines when mounting the wings on field. I might change the way the airlines lead through the gear well, as I plan to case and detail the wells accordingly.

I took a break to enjoy some german beer&amp;lemonade mix!

Tuggs

Topping out!At least sort of....

For the first time I fitted the wings on the fuselage. Wings are a good fit and slop free - not that I would have expected anything different. There is however one little thing I am going to add to the fastening of the wing. There is a small gap between the root rib and the fuselage, which leaves the rib under tension when the screw is tightened.Fix will be a small plywood square to support the rib. 10 minute job.

Tuggs

For the first time the F-89 stood on its own legs. At least with 2/3's that is haha.

I am still unsure whether to go with the scale position of the front leg or the somewhat semi-scale option by kit design. Both has advantages but if I would go only for the looks, the scale position is a must. Using the kit design position would surely save time.I am still impressed with the size of the main wheels. Last steps tonight were to finish the flaps on the remaining wing and to pull the wiring for ailerons. I also put the hatches for the servos back in place and screwed them in.

Next step will be to hinge the gear doors in the wing and the final install of the EZAir Connectors. Once that is done, the wings are finished and ready for paint (or first flight, which I will probably do before finishing the plane).