Topic: 92" Ziroli P-47 Thunderbolt

I always fit some stiff spring in the closed loop lines between unit & servo.....this act as a 'servo saver' to shocks which will inevitably happen, especially taxing cross wing etc......and also allow the lines to stretch when the wheel retracts.

Alternatively, you have the space to mount a steering servo in the underside of the fuz, in front of the fin post.........so the lines will go slack when retracted.

In my mind, the wheel MUST be steerable, as the rubber alone is only usable when running at speed (1/2 way along the take off roll etc...)....for slow speed manouvering on the ground, the tail wheel is essential.

Phil

Interesting points, damn you Neil, now I've seen your cockpit kit again, guess I need to get started on something similar.
Had not thought about putting a servo behind the tailwheel, must check that one.
Phil you're no virgin when it comes to the Jug, do you think it can take 3 servos at the back without too much extra nose weight being called for?

Sverrir,

Even with a servo behind the tailwheel you must still ensure that the steering wires cannot become snagged when the gear lowers. However, with this installation you could use the sideways pulling elastic tensioners on the steering wires.

Tally Hooooooooooooo

Andy

Have you checked out the P47 'Roaring Glory'?...............it's good.    

Don't worry Andy, getting tangled up is the last thing we need 

Watched the first 10 minutes of the video earlier, can't wait to watch the rest   

Shame it's the bubble canopy, but you can't have everything..........

I guess I better pull my finger out, February is here and I haven't started on the wing yet 

The SS-1 formers did not come cut with the short kit so I've made them up, they will be glued later.


Something along these lines will the wheel cut out look like, the final shape will be taken from a blown up 3 views.
Next up, doing some wheel doors for the tail wheel.
Notice the clear plastic film to keep the cloth and epoxy from sticking to the fuselage.


First layer of cloth has been applied.


And here we see them all.


I foresee a hole there in a not to distant future 

Hi Sverrir, you seem to like the wood work so much that you have to suck on it for as long as possible   

It looks as you have some sort of a twist in the last fuse' former relative to the C/C line you drew for the TW doors  Or is it my eyes....  Check it anyway mate ...It'll save you a lot of agony to sort it now (if there's anything that is)

  Johan

I think it's a case of my bad drawing skills and camera angle.
They are a little bit offset to the right, seen from the rear.

But I'll do a check anyway, better safe than sorry and all that 

Just pish poor drawing, I reckon.....................          

Thank you Andy...   I guess 
Johan I guess my building "skills" are better than my ability to draw

Spent a better part of the evening measuring and prototyping for the tail retract location.

Here is the hatch all trimmed up and ready for action.


And here is its footprint.


Here we see the tailwheel at its final resting place, I made an U shaped plate from plywood for the retracts to bolt to, that plate sits on beams that are joined to the fuselage formers.


The hatch will probably be screwed on for future access.

Sverrir,

I................................like it       

Good idea................

Tally Hooooooooooooooooooooo

Andy

Not much going on but here is a better picture of the retract.

The first two pictures show one idea I tried for the tail wheel steering setup but I feel it might be a tad to much trouble to gain access later on if I would need to do some work in that area.




Currently I'm thinking about getting the wire to the right position by running it through a plastic tube. Exciting times

What have you done to your gallery? Or did you have one Svartur dödir too many last night before the update

  Johan

The first two pictures show one idea I tried for the tail wheel steering setup but I feel it might be a tad to much trouble to gain access later on if I would need to do some work in that area.




Currently I'm thinking about getting the wire to the right position by running it through a plastic tube. Exciting times

What first two pictures?................................Have you been on the loony soup again?

Tally Hoooooooooooooooooooooooooooo

Andy

Sorry guys my server was down this morning due to maintenance work on the buildings electronic grid.
Normal services have been restored 

Nice of you to ask Johan  Truth be told I don't like Svarti Dauði.
I've been busy since Friday noon building on a larger scale, we've been working on the new airfield club "house".
http://modelflug.net/myndir/thumbnails.php?album=30
http://modelflug.net/myndir/thumbnails.php?album=31
http://modelflug.net/myndir/thumbnails.php?album=32
http://modelflug.net/myndir/thumbnails.php?album=33
http://modelflug.net/myndir/thumbnails.php?album=34

Sverrir,

Why don't you just bring the steering cables straight through the bulkhead that's in front of the retract, directly to the steering arm.

I don't see the reason for the slave horn and the 'U' shaped guide tubes, what advantage does that method give you?

Confused from England.......      

Tally Hoooooooooooooooo

Andy

I'm scratching the slave horn idea for the guide tubes if nothing better pops up.
But look at how the steering arm on the retract moves when retracted, it goes backward, hence needing more cable or some fancy spring work on the steering line. There was some discussion about it from the lower half of page 4 and forwards.

Nice drill head, do you have to drill for hot water yourself.... Your snakes.....you're confusing the swedes as well  

Please explain for us ignorants...

Re. drinks, I thought Svarti Dauði tasting notes are pretty much the same as for Brennevin or any other Vodka type of booze, it's more of a mouth wash after eating some of the ecological preserved Icelandic dishes  

  Johan

Lol, the wagon comes from Iceland Drilling Company(they own Iceland Drilling UK) hence the drillhead we found.
We are not far from the Blue Lagoon, about 10 minutes drive so I'm sure we could drill some holes around the airfield for hot water.
I guess you are right about the mouth wash bit but I prefer some VSOP over that stuff 

Lol, the wagon comes from Iceland Drilling Company(they own Iceland Drilling UK) hence the drillhead we found.
We are not far from the Blue Lagoon, about 10 minutes drive so I'm sure we could drill some holes around the airfield for hot water.
I guess you are right about the mouth wash bit but I prefer some VSOP over that stuff 

So do I my friend, so do I....

Sverrir,

Yes...................I can see the reason now........................the retract unit is doing the reverse of what you want.

OK, idea.................. instead of the tubes, run the wires around a pair of grooved pulleys. That sounds like a more positive, less friction solution. Two tension springs on the servo horn. Forget the proposed slave horn

I have done a single pulley closed loop version to raise and lower the tailwheel on my Spitfire, to save the weight of a pushrod. You need a friendly native with a lathe to knock you out a pair of lightweight plastic pulleys. 

What do you think?

Tally Hoooooooooooooooo

Andy

Sounds like an idea mate 

Fit springs in the closed loop lines................not only will this allow the lines to stretch when the tail wheel retracts, but it also gives a degree of 'free caster' to the tail wheel, preventing excessive shock loads from rough ground and cross wings reaching the steering servo....................I've had this system in my p-47 for over 250 flights, and I've yet to have a problem. (also had it on the SisT 190 I bid last year....worked well)

Phil

So many things to consider 

Sverrir,

I agree with Phil, but the springs will provide the most tension when it's NOT needed, when the wheel is up.

The least tension when the wheel is down, which is when you need steering control, therefore, some tension in the wires.

You must have already considered this, to arrive at your 'U' shaped tube idea.

If you can find long enough tension springs, that will still provide adequate tension/steering control, but not so much, that you get top 'C' when the wheel is retracted, then I would do it as Phil has suggested.

The 'U' shaped tube/pulley idea reverses the action so you get the most tension when you need it.

I am looking forward to your conclusion.............      

Tally Hooooooooooooooooooooooooooooooooooooo

Andy

So am I 

Thankfully I'm going out to the country for a few days off at the end of this week, where I'll attempt to finish the Hurri and do some post modern spiritual work to reach a conclusion to my tail story. 

Bicycle brake cable has also been suggested.

Any news Sverrir ?

  Johan

Not really, I just came home from a long due time off, spent out in the country side, flying and taking pictures 
But I'll start rolling soon again...











No models were damaged in the filming of these pictures 

So THATS a 3 point landing !
Wing tip  ,nose   ,back 

So THATS a 3 point landing !
Wing tip  ,nose   ,back 

Hadn't thought of it like that 

On another sidetrack, before going on the holiday I spent most of the spare time on the new airfield "house".
Still some small work left to do but it will get there in the next couple of weeks.

Hmmm....got any vacancies for aeronautical engineers in Iceland?

PDR

I'm sure we could squeeze you in somewhere. Might be nautical though 

I'm watching this build with interest, I've always liked the P47 and ina  couple of years I think this could be the one to build, I've already got the plans

Cheers,
Rich

So will it be a razorback or a bubbletop Rich?

Guess it's time to find the tools again. 
I'll need to run the cables and pushrods out of the fuselage.


Decided to go this way on the tail wheel.



Now we are looking more like an airplane and less like a boat.


One of the B-25 pilots decided to check out the cockpit.

Looking like a plane now

I've not decided which, but I know mine will not be green, I like the silver look with a nice pattern, plenty of time for research though.

Cheers,
Rich

Sverrir,

Your B25, pilot type chappie................needs filling out a bit, to fit that cockpit..............

May I respectfully suggest, an urgent diet of seal blubber and Subways with a side order of dried fish and butter............

              

Tally Hooooooooooooooooooooooooooooooooo

Andy

Duly noted 

Doing the internal stuff these days, not a lot of building time coming up until next month, but it isn't that far away. 

The traditional support of control runs over longer distances, so far only the blue.


Hopefully this "great" sketch will give some idea as to where the rudder servo will be in a not to distant future.


Servos for the elevators. Allen servo screws from Modelfixings, very convenient for tight spaces.

I guess we are off until next fall, cya then