AEROSHELDON

My Feedback: (99)

on the twin tanks I was told to mount them so the rear touches the turbine mount area so that is as far back as they go. This seems correct to me as the CG should be forward of that but wanted to see where others mount them. Thanks!

Dave Wilshere

Mine are just forward of the mounts. Maybe 1”

husafreak

My Feedback: (3)

Here’s mine

AEROSHELDON

My Feedback: (99)

Thanks guys

flyer1966

My Feedback: (3)

So do I measure the deflection on the stab at the trailing edge of the surface?

Dave Wilshere

Yes

rcflyguy_26

My Feedback: (8)

Hey guy,
What settings/measurements are you using on the Xicoy balancer for the Mephisto?

thanks, Scott

AEROSHELDON

My Feedback: (99)

HUSAFREAK,

I recall you had tank overflow leaking until you ran the lines higher, but did you go towards the front very much as well?

dubd

Anyone rubbing the V2 5L tanks? If so, how’s the flight time?

husafreak

My Feedback: (3)

I ran the overflow lines to the top of the fuselage cavity (below the canopy/hatch) but I still get fuel being sucked between the fuselage and the wing center section. Maybe an old school vent pointed forward into the airstream like a pitot tube would stop it?

Dave Wilshere

Such an open question! Will depend on turbine and flying style…but I guess the answer is pretty short if you are hovering/3-D 🙂

AEROSHELDON

My Feedback: (99)

Not sure, but I don't want that haniging down so maybe I'll run mine up to the front a bit more. Thanks

dubd

I meant running, not rubbing. 😂

Are the V2 tanks the preferred set these days?

I plan to mostly do precision acrobatics with the occasional hover and flat-spin.

Dave Wilshere

The 5ltr tank was produced to allow countries with a 25kg wet restriction to achieve this weight. In the U.K. the two tanks are still used throughout

Dave

GULDUKAT

I fly my mephisto's with the dual stock tanks. I get about 7-8mins with my routine. The K320 lets it hover after about 3mins of flying. The last 2 mins of the flight are usually the best for 3D. Unless the 5L is needed for weight purposes - I'd go with the dual tanks.

AEROSHELDON

My Feedback: (99)

Do you remove the foam where the brace to hold the pipe goes, or leave it and fill in a bit more Hysol in the gap to the carbon?

Thanks!!

Dave Wilshere

Remove the foam and scuff the carbon.

flyer1966

My Feedback: (3)

Where are you guys installing the connectors for your tail section servo extensions. I was told not to put them on the top due to the heat??? Any help will be appreciated.

AEROSHELDON

My Feedback: (99)

Seems everyone puts them on top, and I wanted a little more airflow so to speak so this is what I came up with....

husafreak

My Feedback: (3)

I just made an aluminum bracket to hold the plugs as far from the turbine as possible.

husafreak

My Feedback: (3)

As I continue pushing my Mephisto to its limits I encountered a failure today while taking it apart after flying. One wing tube seemed slightly loose, just a fraction but it made a cracking sound as I removed the wing. So the CF spar tube receiver had split. I can’t see any damage to the ply ribs and the wing feels solid but there is obviously a split tube and some of the Hysol type glue the factory uses is crumbled.

Back lit crack opening

At the bottom you can see a bit of missing glue

husafreak

My Feedback: (3)

One more showing the extent of the crack, one rib bay.

husafreak

My Feedback: (3)

There’s not much I can do besides seal the crack with a fiberglass patch and fly conservatively until I’m sure the wing isn’t spreading. That tube is completely buried in the wing center section. The only part of it I can access is where the crack is.
The only maneuver I do that I suspect could cause this is snap rolls, I say that because snaps with this beast can occasional be very dynamic. I do snap rolls with all my planes and try to be reasonable but the Mephisto can move quicker than just about any plane I’ve ever had so occasionally I’ll do a snap think, ouch!
But of course I don’t really know when that spar tube split… Just during the flying day.
I’m up to around 70 flights now.

Dave Wilshere

Something supporting the tube most have been moving to burst the tube, if you use the wing spar as a lever do you feel movement?

husafreak

My Feedback: (3)

Yes, I noticed this movement during the wing removal today and that caught my attention but simply inserting the spar gives the same results. Namely movement in the vertical plane, as you would expect from the split allowing it, but no movement fore and aft. So it is a bit oblong. I cannot see any cracks opening in the structure when I apply leverage to the spar tube though, and clamping the structure doesn't close the gap, it looks is as if the play was there all along, but it wasn't. The other wing tube also has a smaller but still noticeable vertical play although that tube has not split. Obviously something elastic had to give to split the tube and now the tube is no longer perfectly round, but the ply all looks good and the glue looks good too. Not deformed. Maybe the glue used has crushed? I'm starting to think this vertical play has been evolving gradually, but the tube finally split today. Anyway, it is odd that the wood and glue do not appear to have deformed but the structure is allowing movement. I don't see any option but to apply fiberglass, then Hysol, maybe soak some thin CA into the wood?