Engine sounds fine for the Mayhem. Not sure about the 3050 servos. I used the HiTech 5645 on the rudder and elevator and the 645 on the ailerons. They are plenty powerful. I think you want at least 90 ozs torque on the tail servos and probably about 70 or more on the ailerons. Anything less than that may not be enough. Battery sounds fine and with the 6 volt you'll get more torque out of the servos (I'm assuming they'll handle 6 volt. Some Futaba servos don't)
Anyways, hope you enjoy this plane. I sure like mine.
Thanks
Barry

Hey Big Barry,

When you used the YS91 on the second Mayhem, did you notice a change in the CG from the YS110 and did you do anything different the 2nd time around?
Rudder servo still on bottom of the fuse?
Battery where?
Any led in the tail??

root



Hey Barry C,

The Futaba S3050's are 90+ torque with the 6V 1400mAh battery @ 1.6 oz wieght - .16sec@60degrees - 4 metal gears - BB shaft - under 50 clams from servocity.

I'm just wondering how many flights I'm gonna get with 4 out of 5 digital servos running during sportflying/non-3D flight.

5 solid no-worry flights would be great

What do you think?

root

Hey Big Barry

I noticed in post#338 that the servo is behind the fuel tank--where's your battery located?? Behind that??

root

PS Did you change the fuel tank from the stock Sig one to a better one as recommended by YS

or did you epoxy the seams and wrap it in strong fiber re-inforced tape to handle the pressure created by the YS?

Or is this just major "overkill"

root...Sounds like good servos. Anything in the 80-90 class are gonna be fine. That's plenty of torque. I use a 4.8v 1650mA battery and I can get 6 flights easily. I fly 13 minute each flilght. I have 2 digital and 3 analog servos. Also I've heard the 6v batteries dump a little quicker but I don't have personal experience.
Thanks
Barry

Big Barry,

Are you there or are you flying?

root

root...On my Mayhem I used the stock fuel tank that came with it. I know many others have had problems with the pressure from the YS. I'm using the YS110 on five different planes. I used the stock tank with each one including the Hanger 9 products. I've never had a problem. I don't wrap the tank or glue it or anything special. I'll continue to use the stock products until I have a problem.
thanks
Barry

What a terrific thread! This is my first post to it, but I've read the entire thing now (and taken notes along the way).

I haven't started building my Mayhem yet (still planning out the build and finishing my previous project--a Goldberg Sukhoi). I have a new Magnum 1.20 4-Stroke set aside for it and I'm planning to move the rudder servo and battery into the tail after reading this thread. I'll still test the balance along the way, but with the 30oz+ Magnum, it sounds like I won't have much choice without adding lead.

Here's my question. I've noticed in several pictures that people have moved the fuel tank back over the wing/cg. I've never moved a tank from the suggestion position. Will the extra distance require a fuel pump or will I be ok just running the fuel lines from the tank to the engine as normal?

Thanks

sgillmore...Don't move the tank over the CG with the Magnum engine unless you add pump. One benefit of the YS engines is they have a pump already. If you add a pump fine, if not then leave the tank forward. Many have left the tank in it's stock position and state it flys fine there. I think you are correct you will have to move the rudder servo to the tail. I did that on mine. Not that hard really. I really love this plane. It flys wild and nice all at the same time.
Thanks
Barry

Thanks Barry...that's what I suspected.

Really anxious to get this thing together, but I don't have the servos yet.

I do confess I haven't read this whole thread.
But I've been flying my Mayhem since last winter, and I've flown the crap out of it.
My big complaint is that I've bronken two of the mylar CA hinges (one on the rudder, the other currently broken on the elevator).

I use a Super Tigre .90, but my buddy has the same plane, and he uses an O.S. four stroke, and it flies it better than my engine.

A great flying plane, I'll buy another when I crash this one. But I'll do the hinges differently next time.

I used the pinned style hinges on mine. I really like the way the movements are. Just no restriction whatsoever. It's my belief they hold up better also.
Thanks
Barry

Barry C,

Do you mean the dubro plastic style hinges with the holes and the chrome pins at the bend points? Don't they leave a little too much of a gap between the wing and aileron?

root

PS: to all who did'nt take into account all the extra's (some manditory-some not)

I just purchased----

- two 6 inch heavy duty aileron servo extensions (for 2 digital Futaba 3050's)
- one Heavy duty 12" Y harness for recommended better 6Volt signal transfer to the same aileron digitals
- a heavy duty 24 inch servo extension for the rear digital servo
- a remote glow adapter so I don't have to wrestle with the glow starter under the inverted YS 91
- better axles just in case of failure
- dubro 16 oz tank to replace the stock Sig so no YS pressure problemo's
- voltwatch L.E.D meter for battery charge status
$50+

Treat yourself to the extras--you and your Mayhem deserve it

I FINALLY start my actual build tomorrow -

root - out

Yeah, those are the kind I used. The make about 1/8" gap. But I sealed the hinge lines anyway so it doesn't look unsightly. I had a couple of CA hinges fail on my UCD60 and a couple more on the UCD46. I decided to not take chances although I've heard many people say they've had no problems with CA hinges. One of the oldest debates in the book. But for me...I build all my planes with the pinned hinges. Then I seal the gaps. Looks nice.
THanks
Barry

oops - sorry

I don't mean to get the CA hinge debate going (it's not the right place), but I'd like to make one comment. I believe the quality varies greatly from brand to brand. I've had great success with CA hinges, but almost never use the ones supplied with an ARF.

I only use SIG Easy Hinges. They are coated with a CA retardant that prevents thin CA from drying instantly. It allows the CA to completely wick throughout the hinge and soak into the wood better before it sets. Another benefit is you have several minutes to adjust the surface before the glue dries!

I highly recommend them.

Hi guys I flew my 150 Saito on my Mayhem yesterday after I through I had the fuel leak stoped.But I didn't stop the leak by changing out the fuel lines ( But ) I did take the coweling off in the field again and this time we did find the leak.The 150 blowed the back gasket and it was coming from there,wWe got a call into Saito too see hoiw they want too me too send it in or they send me the parts and the hobby shop fix it we will see.I KNOW THIS IS A ( MAYHEM ) thred but I just got my new 120 Ulrta Stick with a 120 New Magum on it and the 6 th flight my ( Christle ) in my Hitex Daul Convrosion went out and I lost my plane at full throthle. ( The point is We called Hitex and they told me they would not replace anything not even the Christle,So guys beware if you are useing a Hitex and good luck

Joe

If you use the pin style hinge as I do and don't want a gap, you just need to notch the leading edge of the elevator, rudder, or aileron, and slightly notch the trailing edge of the flying surface. Then you get it as gapless as you want it and still have full deflection. I always notch out for the hinge nuckle.

Steve

Steve, I do the same with the Durbro hinges. I find that a 3/32 ball shaped bur mounted into the Dremmel tool works very well for the notching. I only notch the movable surface (elevator, rudder, aler.....) this allows you to move the control horn back further onto the surface for more stable mounting. Keep in mind if you use this method of hinging, to leave enough gap for maximum desired throws of the control surface.

"if your not afraid, it's not fast enough"

Root

I try to put all of my fuel tanks on CG. I only use YS engines so it works for me. The tank in the picture was from a previouse plane, I hate to build tanks so I recycle. The packing tape was on the tank as part of the instalation in the previouse plane. The tank had a length of tape that stuck out into the fuse so that you could pull the tank out for mainainance. I was lazy and left it on. I have had one tank crack on the seam in the past, it was a hard plastic chinese cheap type, I probly shuld not have used it to begin with. All sulivan, Dubro and other stock tanks have all worked for me and the YS's. The packing tape cant hurt. The Battery is mounted next to the servo. I usally velcro strap my batt's so that I can move them around till I find my CG and then I Ziptie em in.

Good luck with the plane, its a keeper. You will eventually get another plane but you will always have fond memories of the Mayhem. I plan on always having one around, for me its like therapy only cheaper.

Guys,
I just flew my Mayhem for the first time today.

After 2 weeks of used YS91 problems (it's on its way for a repair estimate to Nevada)

I went and bought a brand new Saito 100 and ran 2 tankfuls to break it in on the ground.

The plane needed only 2 ounces of wieght in the nose and balanced out at 5 1/2". The Saito wieghs about 22 ounces with the muffler and the holes in the motor mount are an identical match to the YS91. I'm really gald I swapped the YS 91 to the Saito 100 so Iew with the CG and add tail wieght - which would have been about another 8 ounces cause that's how much the YS wieghs (32 oz. w/the muff)

BTW I put the fuel tank and servos in all the stock set up places that Sig suggests - I think the plane probably weighs the least it possibly could - like in the low 7 lb range.

My instructor buddy fellow club member did the maiden take off at 1/2 throttle and said the ailerons were really sensitive even at LOW rates and gave me the transmitter.

YOWWWSER - what a great experience - being a novice and flying this GREAT plane for the first time!!

(I soloed 3 months ago and flew a Nexstar then Avistar then Thunder Tiger lazy tiger p51)

I had four 8 to 10 minute flights of mild sport flying and my 1400mAh battery was still good for more but my nerves were about shot --even though I greased in every landing and ROG take offs were a cinch at 1/2 throttle with slow and easy climb outs.

I used Powermaster 20/20 and the Futaba 3050 Servos were absolutley fantastic -- so much so, that I think the response time and accuracy freaked out my unexpected instructor.

Guys that don't usually talk much were much more friendly than usual -

i think it just might because they really like the MAYHEM and they enjoyed seeing me HAPPY for the 1st time in 2 weeks!

Thanks for all the helpfull advice in this thread - I was dreaming of this moment of being able to relate "hands on" to all the other Mayhem owners for a long time. Thanks to Sig as well!

root

root...Glad you finally got that beast up in the air. Congratulations on your maiden flights.

It is a sweetheart of a plane.

Thanks
Barry

Hey Mayhem guys, I must be doing something wrong. Set up as is my Mayhem will do only minimal knife edge. These are specs on my plane, inverted Saito 100 on coolpower 15% full synthetic oil, APC 16-4W prop, it has the pants and a pilot, no control surface modifications, the cowl has very minimal modification to clear muffler, weight 7lb 4oz. On an electronic fish scale we get almost 14lb thrust with tires on a hard surface. The plane flys at about a 45 degree attitude (from a horizontal line)and falls down at about the same angle, the plane is flying at about a 90 degree nose angle to line of flight difference. The rudder travel is all the way to contact with the edges of elevator "v". any tips/ideas would be great. Oh, I should mention the CG is set at 6.0 inches. Also, how brave are you 3D hot dogs getting with the CG, and when does it stop making a difference. Thanks to those sharing all the good info/contributions on this thread.

"if your not afraid, it's not fast enough"

nobody...Something is amiss here. I have a YS110 but I can only get about 13.5lbs thrust. (probably because of my high elevation, 4800') We get about 10.5 on the Saito 100 with 30% nitro. I use 30% on the YS also. My Mayhem weighs 7lbs 12ozs, without pants or pilot. So your weight makes perfect sense. I'm not sure your thrust ratings do. But anyways, it still should knife edge like crazy. I have my CG at 5 3/4" and my throw on my rudder is hitting the elevator (almost) as well. I don't even have to use all the throws. Mine will even KE loop.

The first thing I would do is try 30% fuel and see if that makes a difference. The other thing I would think about is how you start the KE. I come in with zero throttle and turn on the side and then pop the throttle to get the nose elevated. Then I give full rudder authority and modulate the throttle and reduce the rudder to where I like what it's doing. I would guess I'm at about 50% rudder throw and 40% throttle to keep nice level KE.

Are you getting a lot of coupling? Sometimes a way rearward CG will cause severe coupling which takes power to overcome. Maybe move your CG forward? I think your setup sounds right/good. Maybe something we're not thinking about.

Thanks
Barry

Barry,

Thank you for your input, I always wondered about the accuracy of the fish scale. I will move the CG forward a bit and try your methods of knife edge entry. I will buy some 30% to try, the high nitro fuel does carry a stiff price when I think about using 3/4 of a gallon in an afternoon. On the other hand, this is a fun way to spend less money than people do in a bar one evening.
.The plane does come to the canopy then wants to invert when flying from left to right (seems to be the direction I try Knife edge.)

"yes I know I'm addicted, no I don't want therapy"

Well, it appears this thread is finally slowing down. I've spent way too much time here reading all the comments and great advice. I'd been salivating over the Mayhems for months. I finally got a hold of one back in August. After an extended build period (fortunately, I didn't track the hours) I have mine ready to maiden. Hopefully this Saturday--if the weather holds. [8D]

Here's how I'm setup:
Magnum 1.20 4-Stroke
APC 16x4W
Hitec HS-645s on the Ailerons
Hitec HS-5625 on the Elevator
Hitec HS-5945 on the Rudder
6.0V, 1800mAh Ni-MH RX Battery
Dry Weight: 8lbs 4oz

If came out a little heavier than I'd hoped, but the Magnum weighs in at almost 32oz and I just couldn't resist the wheel pants or the pilot!

Due entirely to the advise posted in this thread, I moved the rudder servo to the rear early on. I wanted to post pictures of my rudder servo installation, because I was able to get it to the extreme rear of the fuse. It's basically directly behind and in-line with the elevator servo. With a couple small hardwood blocks, it just clears the other side of the fuse! With the servo more towards the rear, the weight is more effective and the linkage is shorter. To pluses in this case. If you setup for the rudder servo BEFORE INSTALLING THE TAIL FEATHERS, you can easily slip a nice sturdy plywood reinforcement plate for the servo hole through the vertical fin slot in the top of the fuse. I was able to lay the fuse on it's side with the rudder servo hole facing up, then slide the plywood plate (top covered with epoxy) through the slot and use two small L-shaped pieces of piano wire to pull it up against the inside of the fuse. Worked like a charm!

Mine balanced a little behind 5.25 with the battery just behind the canopy. In the picture, you can see the receiver wrapped in foam--the battery is installed just behind it under the canopy.

I can't wait to get it in the air!