CARF Mephisto Build thread
07-18-2018, 12:59 PM
#176
Thread Starter
07-18-2018, 03:53 PM
#177
I'm not a cortex user but here's my 10 pence worth:
I only have 13 flights on mine but I have worked pretty hard on the set up. This plane really benefits from taking the time to get the base set up to your liking before switching on the gyros. I haven't even looked at the set up in the manual so not sure what they recommend but have found the ailerons soft compared to the elevators so am running max throw and around 10% expo aileron with the elevators knocked back at 60% travel and 30% expo. I suspect this will be more twitchy than many would like but hopefully it gives an idea of control balance on the two surfaces. The rudder is pretty sensitive as well so I'm running 30% expo there as well. I'm running 16% differential to get it axial as well (not using tailerons).
Mine required mixing Rudder / elevator and rudder / aileron in knife edge flight and some time playing to get the trim of the tail pipe reasonably close. There is a decent Flap elevator mix needed as well.
Gyro wise I've kept it simple - a 3 position switch, 1 Off, 2 low gyro mode vector off, 3 max gyro and vector. I'm not using any heading hold at the moment. My low rate gyro is helping stabilise in wind etc but gives the model a bit more feel and feedback. My high rate gyro is mostly max'd out on each surface - please take care with the elevator set up here. Mine seemed to still have a very small amount of hunting from the elevators at high speed which wasn't always that easy to spot so keep a good eye on it - my elevator gain is the lowest of all the gains for reference.
I was really disappointed with mine after the first flight - my base set up was awful! Now I've worked it through and kept tweaking I'm really enjoying it. I'm still refining things and still learning the plane - I have to admit I'm not a big gyro user so am trying to find a balance where the gyro isn't killing all the feel and feedback this (or any!) plane can deliver.
I only have 13 flights on mine but I have worked pretty hard on the set up. This plane really benefits from taking the time to get the base set up to your liking before switching on the gyros. I haven't even looked at the set up in the manual so not sure what they recommend but have found the ailerons soft compared to the elevators so am running max throw and around 10% expo aileron with the elevators knocked back at 60% travel and 30% expo. I suspect this will be more twitchy than many would like but hopefully it gives an idea of control balance on the two surfaces. The rudder is pretty sensitive as well so I'm running 30% expo there as well. I'm running 16% differential to get it axial as well (not using tailerons).
Mine required mixing Rudder / elevator and rudder / aileron in knife edge flight and some time playing to get the trim of the tail pipe reasonably close. There is a decent Flap elevator mix needed as well.
Gyro wise I've kept it simple - a 3 position switch, 1 Off, 2 low gyro mode vector off, 3 max gyro and vector. I'm not using any heading hold at the moment. My low rate gyro is helping stabilise in wind etc but gives the model a bit more feel and feedback. My high rate gyro is mostly max'd out on each surface - please take care with the elevator set up here. Mine seemed to still have a very small amount of hunting from the elevators at high speed which wasn't always that easy to spot so keep a good eye on it - my elevator gain is the lowest of all the gains for reference.
I was really disappointed with mine after the first flight - my base set up was awful! Now I've worked it through and kept tweaking I'm really enjoying it. I'm still refining things and still learning the plane - I have to admit I'm not a big gyro user so am trying to find a balance where the gyro isn't killing all the feel and feedback this (or any!) plane can deliver.
07-28-2018, 11:33 AM
#181
Thread Starter
Will need careful setting up to get it to sit like you see in some videos. The transitions between wing and vector lift needs full gyro on the vector.
i would start on the back edge of the wing tube and move it back from there once you get some flying in.
i would start on the back edge of the wing tube and move it back from there once you get some flying in.
08-05-2018, 09:18 PM
#183
Join Date: Dec 2010
Location: Victoria, AUSTRALIA
Posts: 105
Likes: 0
Received 0 Likes
on
0 Posts
Tried doing the CG Lastnight, ended up with batterys just infront of the turbine which was very surprising considering some of the pic's i've seen with RX Packs in the nose.
Anyone else find this?
Anyone else find this?
08-05-2018, 09:47 PM
#184
Hi,
Maidened one Mephisto last friday.
I used the CG as per manual.
Flew great and predictable, tried the vector thrust - but CG was much too forward. Will need to move it backward to get the VT to operate properly.
Will try again once done .
cheers,
Ziv
Maidened one Mephisto last friday.
I used the CG as per manual.
Flew great and predictable, tried the vector thrust - but CG was much too forward. Will need to move it backward to get the VT to operate properly.
Will try again once done .
cheers,
Ziv
08-05-2018, 09:57 PM
#186
Thread Starter
i would set the balance to fly nicely as an aeroplane, 45 degree roll inverted etc, then play with the vector. You may well be nose heavy, but I don’t think that’s the main problem. You have a KT 310?
08-05-2018, 10:13 PM
#187
Yes, I use KT310
I agree we need to use the throttle response on the 310 a little different
at 45 inverted it dives a little
I will add some lead to the tail and check again
I use the new balanced tail
cheers
ziv
I agree we need to use the throttle response on the 310 a little different
at 45 inverted it dives a little
I will add some lead to the tail and check again
I use the new balanced tail
cheers
ziv
08-06-2018, 02:56 AM
#188
Join Date: Dec 2010
Location: Victoria, AUSTRALIA
Posts: 105
Likes: 0
Received 0 Likes
on
0 Posts
I have the balanced tail version from factory too and a 310
triple checked tonight and CG is on the rear of the wing tubes with batteries in the front access hatch of the middle wing base.
Not an ideal location but better than dead weight.
triple checked tonight and CG is on the rear of the wing tubes with batteries in the front access hatch of the middle wing base.
Not an ideal location but better than dead weight.
08-12-2018, 03:47 PM
#190
How does this airplane fly without the thrust vectoring? I'm looking at the Havoc and Havoc SS but I do like the look and size of the Mephisto. Its larger than the SS but not as large as the big Havoc.
Thoughts?
Thoughts?
Last edited by IFlyEm35; 08-12-2018 at 03:54 PM.
08-12-2018, 04:56 PM
#191
And the day came!!! First of all a big thank you to my friend and builder JTFDEZ, he did a splendid jod...My Mephisto was ready since a couple weeks back but due to work I didn’t have the time to maiden it untill last week, I couldn’t wait a day more, so after 15hrs of duty time from JFK to Santiago-Chile u headed to my club and maiden it...
what can I say that hasn’t all ready been said, the Mephisto is THE PLANE!! It does it all, and i mean ALL... it is so stable, so precise so predictable and has not a single bad habit... I was shoked after the the first flight of how it handles, it’s so much fun to fly it, definitelly a MUST in your hangar!!
My power plant for now is a KT260 that performs more than good, great power good throtle responce...
since the maiden day I have put 10 more flights on it, also seted the Cortex pro after the 3rd flight and there I was flying 3D, hover , tumbles, flat spins, high alfa staff and it was a joy!!!
Now I’ll start playing with the CG as it is a little forward, here are some pictures of maiden day and following flights...
also to to answer the cuestion about the TV I disconected it for some of the flyingts and did some IMAC flying it hendled awesome!!!
what can I say that hasn’t all ready been said, the Mephisto is THE PLANE!! It does it all, and i mean ALL... it is so stable, so precise so predictable and has not a single bad habit... I was shoked after the the first flight of how it handles, it’s so much fun to fly it, definitelly a MUST in your hangar!!
My power plant for now is a KT260 that performs more than good, great power good throtle responce...
since the maiden day I have put 10 more flights on it, also seted the Cortex pro after the 3rd flight and there I was flying 3D, hover , tumbles, flat spins, high alfa staff and it was a joy!!!
Now I’ll start playing with the CG as it is a little forward, here are some pictures of maiden day and following flights...
also to to answer the cuestion about the TV I disconected it for some of the flyingts and did some IMAC flying it hendled awesome!!!
08-19-2018, 04:27 PM
#193
My Feedback: (21)
I did the preliminary CG check on mine today without the batteries installed. Like yours - mine came out nose heavy. Looks like my batteries will have to go aft of the CG as well. I too was surprised. I have a Jetcat 300 installed as far forward on the mounting rails as possible trying to maximize the distance between the turbine exhaust and the tailcone . I could possibly move it aft a bit.
08-19-2018, 09:07 PM
#194
Thread Starter
You have the latest balanced tails? None of the 6 Mephisto models here have the batteries aft of the balance. With the radio batteries near the radio ledge having the turbine, retract and possibly smoke batteries near the balance is normal with a 300.
08-20-2018, 12:00 AM
#195
Thanks for the pics Dave. Getting on really well with the plane now.
GeeBeeMan - something sounds wrong there. My 300 isn't as far forward as that - it's set for the correct tail cone gap. Surely you tailpipe gap must be massive if it's that far forward? Just for reference 1 rx pack is up in the nose next to the nose retract unit, the other is over the top of where the ducts meet and the other is next to the UAT on the plate over the top of the intake ducts.
GeeBeeMan - something sounds wrong there. My 300 isn't as far forward as that - it's set for the correct tail cone gap. Surely you tailpipe gap must be massive if it's that far forward? Just for reference 1 rx pack is up in the nose next to the nose retract unit, the other is over the top of where the ducts meet and the other is next to the UAT on the plate over the top of the intake ducts.
08-20-2018, 06:53 AM
#196
My Feedback: (21)
I am assuming I have the latest and greatest (weighted tails). I custom ordered mine as an all white one and received it directly from CARF Thailand in late May 2018. As you can see in the photo, I have mounted my Jetcat 300 about as far forward as possible. The Tailcone isn't permanently mounted yet, but is in the proper location for the photo. The gap seems small to me. Andrew - what gap do you have and where are you taking the measurements? I haven't trimmed the front of the bell mouth as ZivBit has, but I intent to.
08-20-2018, 09:16 AM
#199
That doesn't look wildly far forward compared to mine! I've subsequently trimmed off the entire front section of the bell mouth forward of the carbon mounting bracket to get better airflow around the turbine. I can't remember what tailpipe gap I ran - I seem to remember something like 55mm but I could be totally wrong. Unfortunately I'm away with work all week now so can't check until I'm home again.
Last edited by Andrew Bird; 08-20-2018 at 09:29 AM.
08-20-2018, 09:28 AM
#200
Thread Starter
The figure I gave Birdy was 50mm, but 50-55 is what you want. Your non Pro P300 will be a little lighter,but that won’t make a huge difference near the balance like it sits