Nova

Hello, Can i get some recomendations for servo's, battery, and reciever for this big Revolver?
Just got the Plane and power will be Saito 100. i have Spektrum DX7 Transmitter.
I'm just getting back into flying, been away from it several years and i don't know what to go with.. so many choices, 4.8v, 6v, digital servo's, analog servo's????
I'm just average sport flyer, loops, rolls, knife edge, snap rolls inverted etc..
HELP! and thanks for your time.

mike boxtall

If I had a good charger I would go with A123 or lipo. Most digital servos can handle the extra power. It bumps you up to 7.2 volts. Some guys will warn you against, but others will be with me on it. I plan on switching over when I get a decent charger. As for now I am at 6 volt and DS821 servos all around. Dual elevator servos.

Slow and Steady

Hi Paullie, I have been gone for a couple of days. Went to Universal in Orlando. Great time, but was it hot and crowded. As for the EF Yak, as you may know the elevator servos are mounted in the stabilzers. It is a real challenge to work on, in the tight quarters. I stripped out two of the four mounting screws on each elevator servo. This is my 15 ARF build and I can't believe the bad luck. I am replacing the screws with hex head screws and blind nuts. I know this it not the Yak build site, so I will dispense with any more comments, except to say it is a great plane that I look forward to completing. Regarding your bearings, I believe my 91 FX had the same problem, but I could not dismantle it; couldn't get the piston rod off of the crank. I heard they sometimes develop a groove in the crank and won't slide off. May be a good time to try the 95 AX!? Take care, Greg

Slow and Steady

Hi Luchia, I generally agree with the prop sizes you mentioned, but would go with a 10" on a 46 and an 11" on a 55. I run a 13 7 on my 75 AX Revolver 70 and a 13 6 on my 75 AX powered Aeroworks Edge. I had a 91 FX on the Revolver 70 with a 14 6 prop, which I thought had great overall sport flying characteristics (good speed and breaking).

Slow and Steady

Nova,

JR 821 are great servos and should be fine for aileron, but I woudl try a Futaba 3050 metal gear servo for the rudder; especially if you intend to do knife edge and snap rolls. Jr 821 will probably be fine for the elevator if you use two servos, as many flyers have done. If you are going to use a single elevator servo, you may want to use the Futabe 3050. The 3050 has metal gears, 90 Oz torque at 6 volts and costs around $45, approximately $10 more than the JR 821. As you may have read here, there is alot of flex in the 2 56 servo control rods between the support tube and the servo. Some flyers have stiffened the rods by inserting the unsupported part of the rod in a carbon fiber tube directly behind the servo (the carbon fiber tube is just a little shorter than the unsupported length of 2 56 wire, since the carbon fiber tube won't fit in the planes existing guide tube. The 2 56 is buttered with epoxy before being inserted in the tube. Some use thick CA instead of epoxy. My plane would fish tail during knife edge before the wire was stiffened with the carbon fiber rod.

Hope this helps, S & S

wjcalhoun

Nova

My bias is toward A123 / LiFE / lithium iron phosphate chemistry for batteries, but you will have to be careful to calculate how many mAh are used by each flight, and keep track, because Voltwatch devices and even ESVs will not give you a good read on remaining battery capacity. For this reason some advise toward other chemistry. If you go with NiMH, make sure you have sufficient discharge capacity to serve all of your servos current draw during high draw events (max deflection at speed) so that you don't have a significant voltage drop.

In any case, 6v gives you better torque, better speed, and perhaps resistance against receiver brown out, whatever chemistry you choose (NiMH, NiCd, etc).

As S&S noted, for a bird this big, MG servos should be standard.

My personal opinion is that analog servos have had their day, and there is no real advantage, so I go with digitals. Better standing torque, better centering, etc. The only advantage of analog is cost, which can be a cosideration for some folks. Others differ on the analog/digital debate, and I don't want to start that. I simply think digitals are generally a better solution. I would pick servos that have 100 in-oz torque for ailerons, and elevator if you are using dual servos; 140+ in-oz for rudder, and elevator if you are going with single elevator servo.

Take note of S&S advice on rods. 2-56 is pretty marginal for this size plane unless you stiffen with some method. There is a summary post by me back some weeks that capsulizes some of the advice on this thread.

Good luck

microdon2

My Feedback: (47)

Flew my Rev 59 with the OS 61 this morning and used a 12x8 prop - the engine seemed happier than with the 13x9. Also looks like I've got the high-end adjusted correctly, too. Plane few very nicely today. Plus was PERFECT weather - sunny, 75 F and 3mph. Am also rebuilding my other Rev 59 - going to install the OS 70 4S that it used to have. Will use a 13x8 or x9 for that engine. Love how responsive this plane is. It must do 720 degrees of rotation per second.

skipb

My Feedback: (6)

To All-

I believe I have read all the posts and noticed a few revolver 70s with the YS 110 for power. Do any of you who have installed the 110 have any photos available? I am going to power mine with the 110 and was looking for cowl cutout ideas. Thanks in advance.

Skip

microdon2

My Feedback: (47)

Skipb - Here's two shots of a YS 120 4S mounted in a Rev 70. Sorry pics are a little dark.

skipb

My Feedback: (6)

Thanks for the pics, but need one with the 110 since it has an airbox attached to the cylinder much like the 91 and 120 AC.

Skip

Slow and Steady

Only down side to digital servos beside price differentilal is the added battery drain. It is my understanding the digitals require more miliamps and will drain the battery more quickly. I haven't used analogs since my trainer, and the battery drain issue is something I have heard but have no experience to draw from.

pryor808

My Feedback: (1)

I am currently using on my Rev 70the Hobbico 6v Hidramax 2000Mah NiMh with Futaba Digitals S3152's (2) on elevator using a Expert heavy duty servo reverser (1) rudder (2) aileronsand,(1) analogclassicstd Tower S2000 TS-53 for throttle. I fly an average of 5 hard, 15 minute flights and, use up about 450mah. In other words, I can fly all day with plenty a reserve left. Keep things simple guys.

wjcalhoun

Hey Guys

Had my R70 out today in perfect weather. Having a low idle on a switch has made landing pretty straightforward. Getting the engine rpm way down really helps the airframe settle nicely. By way of reminder, OS AX 1.20, 16x8 APC, 9#8oz all up weight.

I can say unequivocally that the book high rates are too low. My high rates are book + 40% (by radio). I was snap rolling the R70, and even on high rates, it described a tight corkscrew, rather than a true snap. My 25% Extra describes a tight corkscrew on LR, and actually snaps on HR. Hence, I think the HR on the R70 needs to be increased (mechanically) a bit if you are looking for that kind of performance. For my taste, the book LR are very tame, but different people have different preferences on that.

I have an odd problem on vertical uplines, as in the entry to a stall turn. This is a straightforward maneuver with the Extra. Enter wings level, pull to the vertical and go up! My R70 pulls R, and needs more than a little L rudder to hold the vertical, almost as if the engine has too much right thrust. More curious, at the top, when most planes prefer to yaw left to the downline, my R70 will not, even with HR rudder. She yaws nicely to the R, or if I hold L rudder, will fall through the canopy in the pitch axis. I might sound as though the plane is wing-heavy right, but she balances laterally perfectly.

Down lines are OK, although admittedly downlines are much more forgiving than uplines. Other trim (CG, pitch, roll, yaw) are perfect for level flight at 70-100% throttle.

Has anyone else noticed this kind of behavior? Can any pattern guy give me a place to begin to look? I have the pattern "aircraft trim book", so I can work through that, but if anyone recognizes this behavior as characteristic of this or that, it would be helpful to me. Thanks in advance.

pryor808

My Feedback: (1)

Wow,

The OS 1.20AX is light. My plane weighs 9.5Lbs with the 91FX????

Luchnia

My Feedback: (21)

This is very similar to my setup except I run Power HD MG servos. I have yet to get many successful flights with my Rev 70. I do have the same battery pack which works fantastic. As a matter of fact, I run the Hidramax 2000 pack on all my planes now. I can fly pretty much all day and they rarely even get down to 6 volts.

I took my Rev 70 out again this weekend but was unable to fly it due to fuel issues. I have been plagued on this aircraft with fuel problems, but this time I think I found it. I just benched a brand new 91 FX and had it tuned in perfectly and then put it on the plane and it starves out of fuel. I have both Bison and Slimline Pitts style mufflers. I swapped out to the Bison and no change...still no performance and starving out of fuel.

Keep in mind this is a new airplane with only 7 flights and 3 of them dead sticks with TWO different engines. While I was running the engine I plugged one of the tubes on the Bison exhaust and walla! she ran like a top! I knew there was not enough back pressure just because the way the engine was performing. I held it at all different positions and wide open throttle and ran a tank of fuel out on the bench with no issues while the exhaust was restricted. I still have not tested in the air because I did not have an adequate restrictor in place for my comfort.

It is amazing to me how some of these engines will run without plugging/restricting the exhaust and yet others require restrictions. I am hoping it does unload in the air and run good because, honestly, I am tiring of the deadsticks on this plane [>:] I haven't even got a chance to really feel the plane out and get some flight time in. Some have said to run a Perry pump but those are close half the price of an almost new engine. At that cost maybe I will work with exhaust restrictor. [X(]

microdon2

My Feedback: (47)

Luchnia - Very interesting problem and solution - I wonder if that's why my OS 91 Fx is running so badly (bought it used). I'm going to try running it with a muffler for a .61 engine - smaller pipes - to see if it helps. Also noticed recently that the short hose running from the high speed needle to the carb had a pretty discinct kink in it - looks like it could have been restricting fuel flow.

And pls let us know how you do plug that one exhaust hole. I have read of this situation before - does anyone know why some engines need this additional exhaust restriction?

Luchnia

My Feedback: (21)

Oh, there is much more to the story. I have one brand new 91 FX and an older one that is like new (less than a gallon of fuel through it). The older 91 FX engine was mounted on a 60 size Stick for some time now and it occasionaly gave me issues and never performed as it should and yet it was in immaculate condition. The weird thing is that it did fly, however with the occasional dead stick and seemed at times to lack power. Fuel systems in the Stick and Rev 70 were pretty much identical three line tanks and exhaust were identical Pitts style. Even my fuel line hoses are about the same length and fuel tank locations are reasonably close.

I recently pulled the older engine down and every componant was in excellent condition. I did replace the bearings just for my comfort. Put the engine back in the Rev 70 instead of the Stick. It seemed to run really well and adjusted out good. I did not run it all that long before flying and that was my mistake. Took the plane off and made one pattern or two then the engine started falling back on engine power, then finally shut down.

So after having about three dead-sticks on my Rev 70 with the older engine I was determined I would not run the older engine until I found out what was wrong with it. I grabbed the new OS 91 FX out of the box and throwed it on the test stand with the stock muffler and cranked it up and ran about 20CCs of fuel through it and adjusted it out. Then ran another approximately 40 CCs through it until she was smooth as silk. I mean this baby was smooth as glass and I knew I had her right!

I put the engine on the Rev 70 and took it to the field. Cranked the plane up and did my fine adjustments (had to adjust due to the Pitts style exhaust). Ran her up to about half throttle, then on to full throttle and the engines did not seem to run well. I thought now this is strange because I had not long took it off the test bench running beautifully. So I let it set for a few minutes then fired it up again and ran it up to about 70% throttle and the engine started slowing down like it was starving for fuel.

This is when I knew there must be something about exhaust and fuel flow. I took a plastic tube and plugged it and then cranked the plane and it ran much like it was on the test bench! I finished running the tank out of fuel with the exhaust plugged and it would tac around 11600 to almost 12000. I would rarely get over 9800 with the open exhaust. Makes you wonder doesn't it? Oh, BTW, I am running 14 x 6 props.

Now I cannot affirm with 100% because I did not fly it yet. I want to create a more secure plug for the exhaust first. Once I do that I will report back and let you guys know my results. I have heard of guys crimping the exhaust but I prefer to plug it. I can thread it and put an alluminum plug in and drill it and put a small screw through it to provide an extra level of security so it does not come out in flight.

I can take either one of the engines and run them on the test bench with the STOCK muffler and they would run like a top tank after tank and idle very smoothly. The new engine being just a tad peppier.

I know this is a long post, but if it helps anyone avoid bringing their plane in and having to do repairs, then it is well worth it.

pryor808

My Feedback: (1)

Ok! Luchnia,

I feel for you and, you need to enjoy that plane. Ok. Your fuel tank in the plane, is it cushioned with foam also, spray two solid squirts of Armour All into your gallon of glow fuel (prevents bubbles) it will not damage anything. Also, make sure your clunk line is not too long inside the tank. Replace all your fuel lines on the plane. There could be a small pin hole in one of them that you can't see with the naked eye. Is the 14 x 6 prop a light weight wood or a composite APC type?. My high speed needle is opened 2-2.5 turns with the composite typen(heavier prop)and. 4.5 turns with a light wooden prop??? it's odd I know but, that's the way the 91FX runs. When you look down the carb barrel with the carb wide open, the small space(gap)between the spray bar and, the low end needle should be about the thickness of a buisness card.

Nova

Thank you Guys for the info and idea's on the Servo's and Batteries!

pryor808

My Feedback: (1)

Nova,

I hope you keep things simple. Well! It finally happened. Folded my landing gear on asphalt (not grass) Yes! its weak, weak and, weak. It was a 10mph head wind when I flared a little to much and,Plop!!!! here are the pictures of the damage. The wheel pants did a good job on the wing. The wood delaminated on the mounting section of the landing gear.

Nova,

Cut a large hole into the fuel tank floor so you can get access to the top of the landing gear plate. You need to reinforce the structure. I had aplied a coating of 30 minutes epoxy but, that does not held if the wood is going to delaminate.

microdon2

My Feedback: (47)

Pryor - Sorry about your gear folding under - what you described is exactly what happened to a friend of mine (I saw it happen) - just a hard landing on a smooth surface. Now, if you're going to add planking to create a new base behind the old one (once you glue it back), as I do, you don't need to open up the gas tank deck - you can do it all from sliding the pieces in through that deck's rear vertical bulkhead. I create two halves of the flooring, using 3/8" ply, and cut it in half to fit it in. Plop lots of 30 min epoxy under and around it. Then sink the new blind nuts, and also expoxy those over (with the bolts screwed in) so they don't fall out. And I use Dubro main gear (btw - I have plenty of stock gear - if anyone wants a set let me know.) Works great. Had a couple of rough landings this morning with my new Rev 59 that would have easily snapped the stock gear.

btw - this morning I maidened my new Rev 59 with an OS 91 2s. Am using a 13x7 prop, so far (will be experimenting). Once I got it tuned up (have the high-end needle opened to 3 1/2 turns) that plane REALLY moves!

Slats!

My Feedback: (1)

I had the same thing happen on another plane using an epoxy coating. I think the only way around it is soaking a 1/4 ply block and then attach it with some triangle stock. Who knows I have seen reinforced stuff get wanked out pretty good and its always a mess. Just ask Egan about that Pryor LOL..... We were both flying together all I saw was his gear bouncing out of the corner of my eye.

Going to tune the MACs pipe for this thing on the weekend.............

mike boxtall

The exact same thing happened to me yesterday evening. Nice soft landing and in roll out she went ploop. Oh well. Now I can fix it properly in time for the fun fly on Sunday. I was expecting it, just not after the first flight.

wjcalhoun

Clearly the main gear plate is too weakly supported on the R70, and maybe the R59 as well.

So far, my reinforcements are holding on my R70, but our runway has tough Texas grass, and ruts from the occasional hog, so it could tear out again.

One fix I used on a 25% Extra, which was VERY lightly built, was to use 2 pieces of 3/4 x 3/4 aluminum angle, about 5" long each, running longitudinally forward to the firewall, where I screwed them in place. A big washer under the LG nut transfered the pitch-axis rotational torque of the LG to the angle, which then carried it to the strongly mounted firewall. That system has held up pretty well, at a total cost of only about 3 oz. If my R70 gear tears out again, I might try something similar, perhaps with 1/2x1/2 angle.

Sorry to hear of your gear failures mike and paul

jet22b

Hey Guys,

Sorry to hear and see another landing gear problem. When my gear fail on both 70" and 59", there was next to no glue on the gear block. Now the gear on all revolver will not go anywhere. Now you will rebuild the landing gear block the right way and be very happy with this plane. I hope that we will not have rain this weekend here in the Great Northwest, because all three revolver is on the charger as I type. Have a great weekend everyone!!! Fly safe and fly hard!!!!

Sonny
aka
jet22b