1/6.78 Scale Hawker Typhoon

[wollins]

 January 09, 2012, 07:51:41 pm »     Ok, got the backplate ring re-done ... used lite ply and had to painstakingly cut it out with my dremel tool. Very pleased with how it turned out in the end ... quite shocked actually with how precise I was able to get it given the tools on hand.

Colin   

[wollins]

January 10, 2012, 09:39:13 am »   
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Wow nice fit! is the rest of the plane finished yet? LOL your practicly cheating as i dont think winter has even started yet
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Thanks Ed ... it took a lot of elbow grease to get that fit. I can't believe that I originally made that ring out of foam ... what was I thinking? Because of the small surface area of attachment lite ply is the strongest and cleanest solution so it's a good thing that the foam one exploded when it did!

As for the rest of the plane being finished ... at this rate I'd be lucky to get it done by my original deadline. I'm still not done with this darn spinner and that wasn't even on my list of things to fabricate! Hopefully I'll have some more time today to give the cone itself its final sanding and then get it glassed.

Colin

[wollins]

January 15, 2012, 02:05:09 pm »         Well, got some time to get back to it and it's coming along. Just some touchups now (where I've circled) and a final sanding/polishing then we can get to the part that will make or break this project ... the balancing!

Colin

[wollins]

March 08, 2012, 11:41:19 pm »       As I'd mentioned from the get go this really wasn't a "build thread" but really something to keep ME accountable. Having said that I'll just be posting about the "non routine" parts of the build.

Latest update ...

It's painted but I have some touchups to do. Also now working on the retractable tailwheel which will also be an electrical retract and will retract forwards into the fuse like the real one does. The reason I mentioned that is because this presents it's own challenges which I will attempt to document in subsequent posts.

Colin.

[wollins]

March 11, 2012, 11:36:01 am »   


  Ok so here's how this whole electric tailwheel retract thing went down. First off since I had electric retracts for the mains I thought that if I got the tailwheel to electrically retract (coupled with the mains) that would be kinda cool and look somewhat scale. I didn't want to spend a lot of money at it since the whole project is putting me in the poor house as it is.

Knowing that the tailwheel wouldn't have to take a lot of force I figured a cheapie Hobby King electric retract could do the trick. It was rated for up to five pounds or so and since this was gonna be a tailwheel that should be well within its specs. Cost me all of seven bucks or so shipped! The fact that it didn't come with a shaft/strut wasn't a problem since I intended to make my own.

OK, the first challenge was that since this was going to be a "steerable" tailwheel it had to be able to rotate. This posed a problem because the retract was obviously set up to accept a shaft that would be FIXED within its assemply. In other words the retract would have two grub screws to PREVENT the shaft from rotating or falling out!

The way I solved this problem was that I "turned" out a groove in my shaft/strut (a regular 8-32 bolt?) so that when inserted into the retract the two grub screws (which I replaced with regular screws) would sit snugly in the groove and prevent it from falling/coming out of the retract while still allowing it to swivel/rotate. Hopefully the pic will make this clearer.

Colin

[wollins]

March 11, 2012, 12:10:14 pm »


Since I was trying to make this as scale as I possibly could I decided to try to make a trailing link oleo type tailwheel assembly. Well, I should tell you that I tried at first to locate such an assembly. I figured that a nose wheel one (like the jets use) would be great ... I found this one.

However these were always out of stock and again in the interest of saving some money I decided to try to make one on my own. If they ever come back in stock I may actually switch mine out. (I doubt it though )

Well, needless to say if you're gonna be doing any precision work (as I imagined this was going to be) you'd better have precision tools. I have none. What you are about to see is made strictly with materials I had at hand, and regular tools. (hacksaw, drill press etc) No fancy machining was performed here. Looks kinda crude but is very functional. I like to call it "seniors's scale"! In other words if you can see it without your glasses then it will look good. Lol!

So the idea was to make two strut pieces/braces (since the wheel would sit in the middle) bridge them with crossbolts and somehow connect this "assembly" to the strut/shaft. Now since this was a "trainling link" setup the strut piece assemply had to somehow be able to swilvel where it connects to the strut to end up in the trailing link position. I therefore had to make a coupler or "bridge" between the two.

Of course I looked around my shop for a piece of beautifully machined aluminum bar stock but failing to find that I made it from a piece of wood. Lol! You will notice in the pics of the crude block of wood ... there is also a pin. This pin was to be attached to the wood coupler in order to stop the actual tailwheel and struts from rotating all the way around. I called it a "strut stop". Subsequent pics will help to make this clear.

Colin

[wollins]

March 11, 2012, 12:36:34 pm »   


  Ok next I tapped a hole in the coupler to accept my strut/shaft. Next was to try to fabricate the "oleo" dampener. Long story short? The geometry was too challenging given the space and angles that I had to work with. Therefore the next best thing was for me to attach a spring on the opposite side (the outside of the assembly) to keep the training link under tension.

This is where my "strut stop" was to play a role. Because the spring was on the outside of the assembly, (the convex side) in the "relaxed" position (no weight on the tailwheel ie: when retracted) the spring would pull it straight ... IF there wasn't a "stop".

Anyways, I think it came together quite well, my only disappointment was not being able to attach the oleo dampener since the spring (while being just as functional) makes the whole thing look rather crude. All in all though it works quite well, looks fairly decent and retracts well. Best part is it came in under the weight that I allotted for it, (1.95ozs as opposed to my projected 2.5ozs) which is great as this plane needs a LOT of weight in the front. So any weight you can shave off the tail end is a huge benefit. I'm debating whether to add retractable gear doors as well which I orginally decided against because of weight but now ... hmmm

Anyways .. at this rate I should be done by 2013! lol!

Colin

[wollins]

March 14, 2012, 09:52:28 am »       Got the retract mounted and it seems to be working quite well. Just have to hook it up to the pull pull lines that it will share with the rudder.

Colin

[wollins]

March 14, 2012, 09:53:15 am »       Now you see it ...

[wollins]

March 14, 2012, 09:54:29 am »             Now you don't!

[wollins]

March 14, 2012, 09:59:55 am »       Here's a video of it in operation. Notice a little bit of a jam on retraction, that's because the pull pull lines aren't connected to keep in from swivelling yet. Even though the lines will be slack upon retraction thereby not providing much tension to keep the tailwheel straight, the weight and drag of the lines themselves should do the trick. In the unlikely event that they do not ... I'll just install some "guide rails" to keep the tailwheel on track.

Colin.

[wollins]

March 19, 2012, 11:48:32 pm »     

Just finished with the exhaust stacks. It's made up of twelve pieces of aluminum tubing pressed in at the ends. These are attached to a couple of lite ply bases and the whole thing is quite light.

Colin

[wollins]

March 20, 2012, 12:04:53 am »       Here you see I've added the "welds" by adding a rough line of epoxy on each exhaust. Next I painted them with a base black coat on in preparation for ...

[wollins]

March 20, 2012, 12:22:45 am »   

The final "weathered" look!

[wollins]

March 30, 2012, 10:40:57 am »       Hardly seem to be making any progress but here's my report so far:

1. Retractable canopy
2. Scale cockpit
3. Scale antenna
4. Landing lights
5. Painting and weathering
6. Scale exhaust stacks
7. Retractable tail wheel
8. Retractable wheel well doors
9. Scale three blade prop
10. Scale cannons
11. Scale Pilot
12. Scale custom spinner

Colin