CARF Mephisto Build thread
12-30-2018, 07:30 AM
#359
Thread Starter
It could not fly or land slower! Weight obviously affects it, but at our meeting Friday in calm conditions the landings were super slow and gentle. It is an airframe where pulling the nose high is not the technique, it lands flat. The flaps are huge and they need a linkage set up as the instructions and a servo with good torque. I have flown one where on the ground the flaps moved 80 degrees, but slow full flap fly bys showed only 45 degrees.
12-30-2018, 07:52 AM
#360
It took me a while to figure out how to land with this beast on out short 150 meter runway. To the point that now I don't need more than half of it to land even with no wind. I have my flaps on factory settings (120mm) and no crow (out of laziness... I probably should put 6-7mm as other suggested here(
I believe that right now I'm about 2.5cm behind the factory cg. Also, I'm not landing flat anymore. I'm coming with the nose up and some power. Landing flat is fine for grass or when you have a long runway. Otherwise it jumps.
12-30-2018, 09:35 AM
#361
Thread Starter
See I’d call that landing flat! It sits slightly nose up on the ground. For sure the better developed JetCats have less idle thrust, so it is easier to slow it up, but with a JetCat P-220 I can take off and land in 40m with a light breeze. Andrew has the P-300 Pro so he can give you a better indication of distances, he flies from two 120m sites.
Some of my guys had moved the balance back, but have moved it forward again for overal handling, not sure where they are in relation to a manual figure.
Some of my guys had moved the balance back, but have moved it forward again for overal handling, not sure where they are in relation to a manual figure.
12-31-2018, 05:51 AM
#362
I ended up using this CG from personal experience, I have now about 80 flights on my Mephisto, I started with a fw CG as per manual but ended up with a much aft CG, it lands nice and slow, I'm still flying with a 260..
If your tank is empty, the plane must drop on its tail when the tail cone is 100 mm off the ground. That setting is good, still on the safe side, I know there are some guys with an even aft CG, but with this setting I can 3D well, it all depends of your tipe of flying and flying experience
If your tank is empty, the plane must drop on its tail when the tail cone is 100 mm off the ground. That setting is good, still on the safe side, I know there are some guys with an even aft CG, but with this setting I can 3D well, it all depends of your tipe of flying and flying experience
12-31-2018, 08:53 AM
#363
I was flying mine from our grass site today which is about 120m as Dave said and even with virtually no wind today it was dead easy to get in with plenty of room to spare. My CG is a decent amount behind the recommended point but my friends plane is closer to the book figure and they both seem to set up and land the same.
I flew the Zimmerman pipe today for the first time in place of the original Carf pipe. I felt I'd gained some thrust, I was hovering with less stick and had good push out. The plane felt more locked in with it as well. I wonder if it's a result of the thrust being cleaner out of the nozzle. That said - I'd happily have stuck with the original pipe if it hadn't deformed at the rear and started jamming the vector nozzle but it's a bonus the change has made the plane a little better.
I flew the Zimmerman pipe today for the first time in place of the original Carf pipe. I felt I'd gained some thrust, I was hovering with less stick and had good push out. The plane felt more locked in with it as well. I wonder if it's a result of the thrust being cleaner out of the nozzle. That said - I'd happily have stuck with the original pipe if it hadn't deformed at the rear and started jamming the vector nozzle but it's a bonus the change has made the plane a little better.
02-27-2019, 10:50 PM
#365
I was flying mine from our grass site today which is about 120m as Dave said and even with virtually no wind today it was dead easy to get in with plenty of room to spare. My CG is a decent amount behind the recommended point but my friends plane is closer to the book figure and they both seem to set up and land the same.
I flew the Zimmerman pipe today for the first time in place of the original Carf pipe. I felt I'd gained some thrust, I was hovering with less stick and had good push out. The plane felt more locked in with it as well. I wonder if it's a result of the thrust being cleaner out of the nozzle. That said - I'd happily have stuck with the original pipe if it hadn't deformed at the rear and started jamming the vector nozzle but it's a bonus the change has made the plane a little better.
I flew the Zimmerman pipe today for the first time in place of the original Carf pipe. I felt I'd gained some thrust, I was hovering with less stick and had good push out. The plane felt more locked in with it as well. I wonder if it's a result of the thrust being cleaner out of the nozzle. That said - I'd happily have stuck with the original pipe if it hadn't deformed at the rear and started jamming the vector nozzle but it's a bonus the change has made the plane a little better.
Thank you!
02-27-2019, 11:20 PM
#366
To be more specific, I've read the V2 manual and I'm looking for photos of how it fits the engine and how it separates from the back part of the fuselage.
02-28-2019, 01:20 AM
#367
Thread Starter
There is a lot of grey area on fitting the Zimmermann pipe. The people that have run them are running into temperature issues, hopefully we will have a conclusion shortly. If you are talking V2 are you actually getting the Frank pipe??
02-28-2019, 03:06 AM
#368
Can you clarify: whats the diff between the Zimmerman pipe vs Frank pipe?
Chet
02-28-2019, 06:44 AM
#369
Would you recommend waiting and staying with the old pipe even though it got deformed and jammed the vector? (I was and to bend it back to it's original shape, so maybe it's fine?..)
Can you tell me more about the temperature issue? How did you notice that?
02-28-2019, 08:24 AM
#370
Thread Starter
Completely different! If you have the Frank pipe follow the install manual and enjoy! Andrew had the original deform also with a 300 turbine, but another 2 have been perfect even with the 300's!
03-01-2019, 12:28 AM
#371
I'm done with the installation of the new pipe! It took some figuring out just like the build of any Mephisto, but I really like it!
It's the same weight as the previous one, bigger diameter and the beauty of it, is that the pipe protrude into the vector so the airflow is seamless. The new vector is HUGE compare to the old one. Also, the new pipe came with a built in, 4mm smoke tube. very handy! (I can't count the amount of time I was bumping my leg into the old brass tubes for the smoke as those were sticking about 3 inches behind my engine. - no more!)
With my KT320 the pipe was too far from the back of the exhaust (50mm) with the original settings. I drilled new holes and now it's 22mm.
3mm plywood supplied with the new vector. Original trust must be 100% perpendicular to the vector. luckily, mine was.
I had to shorted the pushrods - 65mm
That's the original setting of the 50mm with the kt320. shortened to 22mm.
It's the same weight as the previous one, bigger diameter and the beauty of it, is that the pipe protrude into the vector so the airflow is seamless. The new vector is HUGE compare to the old one. Also, the new pipe came with a built in, 4mm smoke tube. very handy! (I can't count the amount of time I was bumping my leg into the old brass tubes for the smoke as those were sticking about 3 inches behind my engine. - no more!)
With my KT320 the pipe was too far from the back of the exhaust (50mm) with the original settings. I drilled new holes and now it's 22mm.
3mm plywood supplied with the new vector. Original trust must be 100% perpendicular to the vector. luckily, mine was.
I had to shorted the pushrods - 65mm
That's the original setting of the 50mm with the kt320. shortened to 22mm.
03-02-2019, 03:12 AM
#372
Here are a few pictures of my install of the V2 Pipe that I took yesterday...
by the way how are your wheel brakes setting guys??
Does you mephisto brakes hard?? Mine just slow it’s down... my rate is 1/1 and setted at 100% 🤔
03-02-2019, 11:04 AM
#373
The brakes on mine aren't very strong. At least it lands nice and slowly 
Hopefully I should have a solution for the Zimmerman pipe soon and be back up and rolling.
Hopefully I should have a solution for the Zimmerman pipe soon and be back up and rolling.
03-03-2019, 07:36 AM
#374
Mine used to break real hard and slide. I changed the settings and when I turned on the abs and gyro it's only slowing down now. But I prefer it like that.
It takes time to get used to the residual power of the 320. Also in a few rare cases when there was no wind at all and I was too fast, I shut the engine off in the final.
Another option which you should look into is the settings for deccelleration. I'm using jeti, and when I compared the graphs of throttle vs rpm, I noticed that it took my engine's rpm a good 5-7 seconds to go down from 50% to idle (after ideling the throttle). Changing the default deccelleration from 012 to 006, helped a lot. (These are settings numbers, not seconds).
