Delighted to report I had two perfect flights with the Mig yesterday, and it’s still fully serviceable. I have fitted the new Hausl pressure regulator and gear retraction, and lowering, was about 6 seconds, fine.

Peter H is making a new brushless pump and I will fit that soon acting in parallel with the current pump, giving hyd. redundancy.

Really enjoy flying this machine, it handles so well.

Now to refresh the paint and add a cockpit!

David.

Great to hear yours is still going well after all these years David. It’s definatly a model that puts a smile on your face every time.

Mth hidraulyc

The new(ish) hydraulic pressure controller is the one of aluminium rather than the earlier black plastic unit.
The further addition I have made is a pressure guage in the air pressure line to the controller to ensure I have a precharge pressure of 10 bar, 150 psi and no more, to prevent damage to the diaphragm in the unit but still able to get an output controlled pressure of 10 bar.
I have also added a Festo pressure guage ( this is not the normal air pressure guage but a special hydraulic guage) in a tapping from the pressure output to monitor hydraulic pressure when I switch on the unit prior to flight.

Yesterday it it all worked perfectly!

Edgar, I got mine direct from Peter at MTH Hausl.

I have not not yet added the Festo controlled valve as the servo actuated locking valves are working, controlled by a Jetronics unit. I will try the Festo valve later in the year.

It it has been an interesting challenge !

David G.

Guys,
My Mig is clocking up the flights and everything is working perfectly, and an absolute delight to fly.

However, a heads up:

On it’s last flight today, the starboard stab. fluttered. Reducing power and slowing down stopped it and the Model was landed normally.

Examination showed that the holes in the stab. where the bolts transfer the torque from the stab. Shaft. had elongated allowing “play” . There appears to be no other ill effect. I will report further after a close inspection of the servo mount and arms if I find any problems.

I have modified the springs in the MLG struts so that they compress about 1/2 inch with full fuel load. Seems about right and gives the jet a more scale stance.

So, check that all is snug where the bolts go through the stab.

Hi David,

Lucky got got got her down safely. I expected that might be a problem as the threads on the bolts load up on the carbon tube in the stab. Carbon has very poor abrasion resistance.I glued in a aluminium plate into my stabs prior to drilling my holes through my pivot rods. I then covered that with 100g/m carbon cloth and burned rivet detail back in. In fact I re-engineered my whole back end. I machined new pivot rods out of 7075T6 aluminium which was stiffer torsionally that the carbon rods I had. It is also a good idea to tie the pivot tube rigidly to the servo mount too. I found there was slop due to flexure of the pivot tube at the inboard end under load.

i can post some pics of my setup if you like.

The yellow control arm is the one I bought from Rudy Joubert in SA. I elongated that with 3mm Ali plate arm extension for better leverage. Triangular 6mm ply with lightening holes ties servo mount to pivot tube and encircles inner end of pivot tube. No flex now! Control arm is cross drilled and clamped on so that is going nowhere. Above servo is mounting for Ali heat shield plate I made to protect servo.

Hi Craig,
Thank you very much indeed for your input, extremely valuable and much appreciated.

I will try and copy your installation it looks really good.

First step is to reinforce the stab tubes where the bolts go through with the aim of reducing play to zeros to make them bullet proof, or nearly so !

I also use Rudi,s arms with a single servo, JR 6311, same torque as your Futaba servo.

I hear on the grape vine a new Futaba servo is coming with 75 kg/cm of torque, might retrofit with those if they are suitable size wise.

The jet jet is so nice to fly, and the hydraulics working perfectly ( the system still has pressure in it after Fridays flying) I will get it airborne again soon.

There are some nice shots of mine flying on the Classic Jets report thread.

Good luck with yours!

David.

Hi David,

Thanks for your comments.

I had originally fitted jr 6301 servos then tried the futaba bls 177’s. The 177’s blew the jr’s away wrt centering and tightness in the gear train so I stuck with them. I am a long time jr user but the futaba servos seemed far superior. I have also heard that a 75 kg futaba is on its way. Would be a great option. My whole mig is now fitted out with Robbe futaba sbus setup and a mix of futaba 177’s on the tail and 8911’s in the wings, KST x10s on the rudders. Still finishing the final fitout but I am loving this thing! Major engineering exercise but if you live that sort of thing as I do then it is very rewarding as you know. Will check out your pics.

Solid looking set up there Craig. Top job mate. Good to hear you got her down safely David.

Thanks guys. Yes it IS an engineering exercise, in itself very rewarding.
Seems my Mig is blessed, engine failure, flutter, but she survives, perhaps repaying all the effort I have put into her.

It it was such a model flying pleasure to be doing large, smooth Aeros against a clear blue sky on Friday, ( bit like flying in Australia in our current heat wave) the black , red and yellow shows up so well.

Craig, I have been asked to review some new servos for RCJI so will take a close look at the 177 and the new 75 kg unit.

I have got a couple of the Ditex servos, brilliant devices, but not as powerful as I would like for the big Mig stabs.

David.

ps. The new Futaba servo is the HPS A700, 74 kg/cm .12 transit time, brushless motor. Same size case as the 177 and JR 6311.

Stab repair done. It was found that the tubes in the stab. Had a wall thickness of just about 1mm and they had to transmit the torque via the two bolts from the main shaft. The holes in the stab that fluttered were elongated.

I removed the skin in the area of the bolt holes, 5.5 cm by 2.5 cm to reveal the carbon tubes and surrounding balsa structure, the voids were refilled with epoxy and milled fibre.

3.5 mm carbon plates were hysoled to the tubes, top and bottom, drilled to receive the bolts. The lower plates received the bolt heads so now the bolts contact 9 mm of carbon instead of just 2 and the foam skin, much stronger and zero slop.

Two of of the new Futaba 700 servos have been ordered for max flutter resistance and I will probably copy Craig’s structutpral upgrade for the servo mounts.

It will fly again as soon as the new servos arrive, but I do encourage you Mig owners to pay close attention to this area the Mig could not survive loss of one stab!

A wonderful flying machine !

David.

Sound good David. Can you post some pics of what you did? Do you have functioning ailerons on your mig?