Jump to content

Rudder and tail wheel control horn


Chris Walby
 Share

Recommended Posts

Advice please.

I have a BH Mosquito that uses a long tail wheel rod that goes through the tail wheel bracket (plastic block), through the fuselage through a steering arm and then up through the fuselage bent 90 degrees with the rudder (epoxied in).

The issue is no matter how tight I do the screw the steering arm slips on the tail wheel rod on the bench and moving

it about.

No a problem if the tail wheel moves, but as its part of the rudder I don't fancy flying with a large dose of rudder in set on way and my thumb on the stick in the other!

Options

Take the screw out, Loctite the arm and a long grub screw in place

Try in the very limited space to move the arm an file a bit of a flat on the tail wheel rod

Engineer it so the tail wheel is not part of the rubber/steering arm assembly

Anything else?

Each option has some merit and a downside, but what have others done with success?

Thanks for your time

Link to comment
Share on other sites

Advert


Right Chris, thanks. Mechanically your wheel lever is longer than your control horn, so the wheel has a

Mechanical advantage over the control arm.

I have, in the past, on thin bar like this, replaced the soft Philips screw with socket cap head bolt that allowed greater tightening,

and reduced the advantage at the wheel by shortening that leverage.

Alternately, the whole assembly could be built up and bent to shape from thicker piano wire

And a flat area ground on for the control arm location

Link to comment
Share on other sites

Cheers, the issue is compounded by the fact that tail wheel rod is also goes up into the rudder.

Plan A unless anyone would like to chip in, Replace the screw for a Allen cap head and Loctite it on.

Other options seem to require significantly more/complexity, but if I do then move collar up & remove tail wheel, then fit castor type behind original.

Despite having both props in same direction it does not yaw on take off so a bit of rudder & castor wheel should be ok.

Link to comment
Share on other sites

  • 1 year later...

Hi Chris, I have exactly the same problem with my BH Mossie. What a kack design! Seeing as I bought the plane secondhand by unflown is probably why it is still in one piece as I saw another post where the plane spiralled into the ground on its maiden. Problem is once the plane is built you can't get this horn out so I have opted for filing a flat on the bar to stop it from turning. How did you fix your problem? Peter.

Link to comment
Share on other sites

Another possibility might be is to provide separate servos for the rudder and the tailwheel and put them on separate channels. You could then do the file a flat on the tail wheel trick. Mix it in your tranny so the tail wheel is a copy of the rudder (not the other way round!) and bob's yer uncle, no danger of a mechanically stuck tail wheel pulling your rudder over and no dodgy epoxy joint between the tailwheel and the rudder system.

BEB

Link to comment
Share on other sites

  • 2 weeks later...

Be warned.

If a tail wheel can cause the rudder arm to slip, 100% it will on the first bump. The mosquito flight will be very short! ask me how i know.

I bought this nice model off the estate of a fellow club member but this one fault has been its downfall (3 times). Each of my improvements proving inadequate.

The grub screw was swapped for a cap head screw but even this didnt give enough grip. Loctte also failed. Mine has now a cap head screw locating onto a flat on the shaft, holding a solid brass arm and has been silver soldered too.

Best solution is independant tail wheel servo which i will try if theres another iteration of this problem!

The mossie now sports an easy to repair night fighter black with home made spinners!

imag0087.jpg

 

imag0234.jpg

 

Edited By dave windymiller on 13/08/2018 22:32:59

Link to comment
Share on other sites

Nice one Dave and glad to hear you have (hopefully) sorted an inherent issue with this model.

I have to admit that I done nothing yet as I don't like the idea of all the aggravation of another servo and the consequential grief to get the C of G back to where it should be.

If you have any photos of your mod it would be appreciated.

PS what set up are you running?

Link to comment
Share on other sites

Unfortunately I cant show any photos as its hidden inside the fus until its next crash!

Im not sure of the plan its built from but I think its an adapted version of the BH plan. Its 69" span and the fus is in two sections, the rear half is stepped behind the wing and behind the cockpit. Its got 2 X la40s swinging 10x5 3-blade props from master airscrew (about 3 quid each from hobbyking via hongkong!) .

When it all goes well its beautiful in the air. I have the ailerons up a few degrees to prevent tip stalling plus both engines point outwards a few degree to hopefully minimise yaw on a dead engine. Its got no flaps! It did have a clear nose section but since its first crash, its now the fighter solid nose version(never got round to adding cannons). The eagle eyed would spot the wrong canopy for the NF version!

It became a labour of love after 3 rebuilds!  I felt I owed it to Tony Bowler (RIP) who built it.

Edited By dave windymiller on 15/08/2018 13:25:41

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...