well truthfully I wish I had ordered 1 of each... but I was in a hurry and grabbed 27x10s and no 26x10.

I am told brand new the engine turns 28x10 at 6000 on canisters.. after 2 hrs it hits 6200. Since I will be running a pitts muffler numbers will be less.. but I was curious so I thought I would try the 27x10 right off the bat.

The Pitts muffler I use is the one sold by RCShowcase It is a Supersonic
the setup was new -engine propmuffler -I simply bolted it all together - added 32-1 Mobil with pump gas (91) and on first tank cool , the engine turned almost 7100 then loosened up easily 7200 .that is on the ZM 26x10!!- the other 26x10 's turned mid 6000.
Bambula and menzS
all mufflers are not the same just like pipes or cans the differences can be huge.

Yes for a 23 lb model and a loud Pitts in cowl - the 26x10 is a good choice for best power
but in that I personally dislike noisy setups - I use -when at all possible a silent can or a full pipe -and the power with the pipe setup right can be 30% better easily. still smooth, cool running, nice transition etc.. no loading up in any position.
I guess I will have to borrow a 28x10 Mejzlic just to "see" once more what the real load difference is with the 27x10
It is easy to get tricked if the reading is done on a 27x10/28x10 which is NOT the std ol model .

I may end up with a can setup sooner than later.. I haven't played with one before so we will see what happens

As a suggestion - get the largest can you can fit - on a short header - the JMB is still tops in my book as it is priced well has really good sound supression and works best on shortest possible header . the wrap around header also works - the shortest one is a bit better . no big deal.
The large Supersonic muffler for Super 80 (I guess you have one?) also works much better than the smaller in cowl types - noiser but more poop. make an adapter plate and try it on your new engine .
A tuned can - different ball game - these can work well or bite you in the butt. they are simply a tuned device which need to be properly set in length for the rpm band you are after -like a pipe .
No reason you should not get power readings similiar to what I get -if you use same stuff- set same way . no secrets here .
Tho our altitude is higher - all in all the same stuff reads the same way - -actually I get less power -tho the air load is less on th prop it pretty much balances out - read up on snowmobile etc., setups where they try to get more power at altitude - these engines suffer same losses as any IC .
I had a clown on another venue try to explain how readings at higher altitude were not -could not be accurate -
there are volumes of info which show how the prop losses ,engines losses relate - the latest chart Pe Reivers makes available is a good one to poke in numbers and se vas ist!

Thanks for the advice!

My buddy had 2 of the RV-Js bought 4 months apart with a super sonic pitts. Maybe he had a smaller one.. after 3 gallons we could still only get 6300 out of it with a PT 26x10. Both engines were identical as far as power.. although we used the same muffler on them... could have been a muffler issue.

I don't have any PT props so I can't say -- here is a pic of the muffler I have

Dick I will have to compare pics...

OK well it's officially mounted after getting some longer bolts today while driving around for work.

I am missing one pic for some reason... the first one outlines where I thought I would start to get an idea before I started cutting a big hole.

After the hole was cut and a space made so the needles could slide through the actual location was more to the right. So far so good.. doing landing gear, starting radio install tonight and have to do the canopy.

Weather check looks to be 10-15 on Sat and Sunday with sun.. looks like we are well on target to fire her up Sat. morning.

The cowl is roughly finished.. cut outs are still a bit rough but I will be trimming them off with fiberfinish from Maubid.

You will notice in the front middle there is a square opening.. I decided I would build a 6mm depron square with no bottom that directs the air directly over the center of the head.


I needed a fairly long exit since I am using a pitts muffler.. I am thinking airflow should be good the way it sits. Still pondering that one.

3W specifically includes and tells you to make sure you use the grommets they include to mount the ignition which allows from proper airflow around the unit. They do not want you to use foam under it.

yeah baby u r moving!

Should work- a couple of comments - may/may not be too relevant .
getting a good airflow around thru rear of fins next to the can really bugged me - that's why I did that tunnel which makes air path under the can then out thru that lipped thing at bottom edge of aft lip of cowl. In checking out burned up engines years back -the rear of the bore adjacent the muffler can is a "hot spot".
If my new eyes are right , your muffler can is smaller volume than the one I use - N/Y? again, just a comment -

I think my little ram air intake should keep her cool with all that opening in the bottom. This muffler is pretty close to the same size.. maybe a bit smaller.


Well servos are in, canopy is on. Just have to do linkages, final radio install, engine servos, and check balance. I havent done the rudder yet.. not sure what the outcome will be yet... but she's getting close.

One more night should do it!

Fire that thing up!

I have a 3W 80xi/supersonic pitts in my 35% Extra 260 and it turns a Bolly wood 26-10 at 6300 rpm. Pulls good but the plane weights 25lbs so things could be better. I just ordered a ZM 26-10 for it and with the increase in rpm ( Dick, you say it happens) I am hoping for a little more pull. Still...... its good but looking for more.

I think the added 5cc will give more, but enough to turn a 27-10. Hmmmmm, maybe.
When the 80 Xi came out it was going to turn a 27-10,
I like my 3W, it has been good to me!

I think they should have just went to 100cc.

Good luck with that sinergy. Your installation looks like mine, and cooling should be fine.

Sinergy,

Your cut out on the cowl around the cylinder looks good for air flow, however, I'm wondering why more people with singles in 260's don't block off the portion of the cowl around the prop and spinner. It would seem that a lot of the air would enter this area and pass over and around the motor. The reason I ask is that I'm getting a new Extra 260 and 85cc motor and want to make certain I've got max airflow past the cylinder for good cooling.

Can anyone say if blocking off around the spinner would be necessary or a good idea for cooling purposes in a 260 with a single.

Thanks - Jaketab

Well... I got a late start lastnight... didn't get started building until 11pm I did work till 4am and then just woke up and will start building after coffee is ready. Little bit tired for 5hrs sleep... but I said I would start the review on Sat and that's what I plan on doing! I have about 3 more hrs left.. so I expect to be at the field by 2pm.

I don't have an accurate reading for weight.. but I am looking to be around 23.5 pounds. We will find out about that 27x10 soon enough! I plan on getting a flight or two.. then letting it run for an hr at 2300 rpm and getting another flight or 2 with more numbers.


As far as blocking off the top.. I will be getting some temp numbers so I will have more answers on that soon

way to go Vampire i like that motovation...

Some food for thought - simply running it at 2300 for a long time --is just the factory's way of saying "please don't burn it up."
a constant long, steady rpm is not a good way to break in any engine -I don't care who makes it.
leave the cowl off -and fly it around at different throttle settings on the smaller prop - a 25/26x10 for a few flights
the whole idea is to let the engine seat without excess load(heat.)
Once it gets limbered up- then run the 27x10 . I will go one step further on this - runn8ng it steady at 2300 CAN cause more problems in getting it all seated -than simply flying it at varying speeds on smaller prop and varying speed low -med- high.
WHY? simply put, you may never get the thing to operating temps and if you do the 2300 long run-- cowled - setting there at low speeds -- you can overheat it .

Makes sense...

It was just an easier way to time the amount of run time so that if I get my hands on a DA I can do a simil.ar procedure. I will just fly her around

Thanks

Even with a 27-10 it will be fine for break-in I think, just don't keep it full power. I run mine slow and easy for the first few gallons.

Nice slow flying, its a good way to get a good feel for the plane anyway. Mine can be slowed way down, even at 25lbs, and its fun just doing slowwww inverted, upright, loops, rolls, spins, and a little full tilt stuff just to see what it can do. The 3W is very robust, mine has been outstanding, no overheating at all.

Hey guys... sure some were wondering where my initial reaction is..

Long story short I spent 15 hrs straight getting her finished.. had more work than I figured, combine that with 4.5 hrs sleep and I was a slow worker. However the good news is I am done... soon as I finish training at 12pm I will be able to fly my own plane and will have 7 or 8 hrs straight to get some flights in.

More soon!

Well she finally flew today... I got 4 flights on her and then came across a rudder linkage issue which grounded me. Flights were short and sweet ranging from 10-12 mins with the first one being about 8 while I worked off the first flight gitters and got the madian out of the way

Intial impressions I was a little bummed about the top end numbers. Transition was extremely good and you can tell she is full of torque but the intial number was 5600 peak on the Xoar 27x10. Clearly a bit too much prop for it. However I didn't have a 26x10 to try so I thought I was just fly her and see how it did.

The plane came in at 24.28 pounds without my ignition battery in it.. 3W wants a 6v pack in there and I didnt have one with me at my buddies place to add with the scale.

Anyhow.. the field was packed and a bit windy so I figured I would put some flights on the plane and get it dialed in a bit while I got used to how it flew.


On the 2nd flight I noticed an audiable increase in pitch at full throttle... it appeared the engine was already starting to wake up. I was running Lawnboy 32:1 with 93 oct. gas (3W calls for high octane). For the 3rd flight I had to tweak the needles because the low-end was noticeably rich. As I retweked the motor and tach'd it my ears were correct.. she was peaking at 6050 and I backed it down to fly it at around 5880.

It def. has a nice smooth idle / transition and hauls around the 260 with authority. Hovering has plenty of pullout and verticle lines are effortless it def. doesnt loose any speed and a couple of times I let her climb exremely high.

Unfortunately no video today.. I wanted to get the plane dialed in a bit better. I had planned to film the 5th flight until I noticed my rudder linkage had a bunch of play in it. I had noticed trying a KE loop that I had lost all my rudder power and found the problem.


Needless to say overall the engine is doing quite well.. I will have a 26x10 asap. The guy who does video for me is meeting me Wed so I wll get some then for sure.

Oh I should also mention engine temps where a steady 180-185F

Sinergy, try a Vess 26A, after trying all of the 26x10 props that one is night and day better than the others IMO.