BlueMax3

My Feedback: (1)

Bob,

Glad to hear you were able to land your plane safely after the engine died. At least it happened when you had some altitude. Sorry to hear about the threads issue on the muffler. When I purchased my engine and supersonic muffler from RCShowcase it came with regular lock washers and so far they have not loosened. I check them regularly and they have stayed tight, even without any locktite. Hopefully yours holds with locktite, but perhaps you could add lock washers as added insurance?

I am by no means an expert with gas engines, but the guys at RCShowcase and the documentation that came with the engine said that if the engine sags during a climb, it is an indication that the H mixture may be too lean. Having one of the "gas guys" check it out sounds like a good idea.

Glad to hear the engine is working well for you otherwise.

Travis

BlueMax3

My Feedback: (1)

My Roto25 seized today, so I will find out what RCShowcase's service is like.

First flight was perfect. Mid-way through my second flight, I noticed something was different about the engine. It seemed like it was losing power. I brought it around dropped the gear and flaps and was on the downwind leg to land when the engine started sagging and then stopped. I immediately turned onto base, but wasn't going to make the runway, so I retracted the gear and ditched it. Luckily, there appears to be minor damage to the plane, but the engine is seized. It was hot today, around 98 degrees at the field, but I don't know why it should have seized. I am using Mobile MX2T at 32:1, the high end is a little rich and my prop is an APC 16x12. I've got 1.5 gallons through it. My rpm on the ground was 8200 and in the air 8800, per the ignition tattletale, and I have excellent airflow over the engine, so I don't think I did anything wrong.

Thoughts?

Travis

rmh

Engine seized?
Only one explanation- too hot -
Today I flew my ZDZ50 YAK- and first flight - engine felt "soft" applying power on uplines also slower - so I listened for full rpm on level flight - -yes it went to full-
Landed - enrichened high speed needle 1/4 turn
filled up flew again - now the uplines were back up to power-- sharp instant full rpm in level flight.
My point - It is hard to hear heat problems -- the engine never gurgles - may sound fine -but IF it ever sags even for an instant --stop !
Once you have reached the "sagging" point - you are far too lean.
Frankly I wil be surprised if they honor any problem which shows scored piston/ring etc..
Not trying to wish you bad luck but having done this for a loooong time - I find most engine mfgrs will fix a multitude of engine problems --except ones caused by overheating.
In hot weather (today it was 102 here -I quit before it hit that ) you should try for an over rich mixture if possible -
heat buildup in ambient high heat is extremely rapid.

BlueMax3

My Feedback: (1)

Dick,

As usual, thanks for your sage reply. I couldn't turn the crankshaft using the prop, so I am assuming that it is seized. I don't know how it could be anything else. If they don't fix it under warranty, I hope it doesn't cost too much. The thing I am worried about is that I thought I did everything right and had the mixture rich. On the flight before and that flight it didn't sag or have any indication of leaning in climbs. I was just doing level flight at about 1/2 throttle when I noticed the sagging and then as you said, it was too late.

Travis

Fredde1

Will the roto 25 fit a funtana s90? can i use the stock carb arm or do i have to buy a new steering arm? i live in sweden so we dont have 3/16 steering arms.

BlueMax3

My Feedback: (1)

I got a call from RCShowcase today with an update on my Roto25. It turns out the engine did not seize, but the hub was pressed up against the case, making it feel like it was seized. They took the engine apart and added a shim to prevent this from happening in the future. He said the inside of the engine looked great and that I did nothing wrong. They have repaired it and test run it and it will be on its way back today--no charge. Thanks to RCShowcase for providing great service.

Travis

Richard L.

My Feedback: (24)

That's good news, Travis. I hope the same problem doesn't happen to mine.

BlueMax3

My Feedback: (1)

Richard,

Are you using yours yet? If so, in what?

What I don't know is whether the problem with my engine can be detected by visual inspection without taking the engine apart. The technician claimed that no damage was done to the engine, so at least that's good news, but it would be good to know whether this is an isolated case. I should have asked him!

I can't wait to have this engine back in my Hurricane, because other than this one problem, it really has been great!

Travis

finless

My Feedback: (6)

Well I had another dead stick with my Roto25 last weekend :-(
Again the muffler came loose and this time I used RED lock tight.
I am going to drill holes in the muffler allen screw heads and run stainless wire to seize them.
It should take care of them coming loose.

Now I have another problem and since I am still learning how Gas engines work I need an opinion.
If I throttle up and then back down the idle is high and then slowly drops to be too low and sometimes quits.
The muffler was only slightly loose so I am sure this weird idle movement is what caused the dead stick (I was in a hammer head).
Any ideas why I am now seeing this happen? Maybe too rich on the idle?

Thanks,
Bob

BlueMax3

My Feedback: (1)

Hi Bob,

According to the chart in the FAQ on the RCShowcase website, those symptoms indicate a lean condition on the carb "L" mixture. Perhaps richen the "L" mixture a tiny amount.

Travis

Tsutomu Mabuchi

My Feedback: (1)

I made the throttle arm by soldering a 3/16" wheel collar and brass sheet.
And put it on the opposite side of the stock carb throttle arm.
I slipped the spring off the carb not to give the servo any stress.

Tsutomu Mabuchi

Tsutomu Mabuchi

My Feedback: (1)

Fedde1,

The pics left.

Tsutomu Mabuchi

Fredde1

thanks.
How did u do with the choke? do u have a extra servo for it?. is the choke important to have mounted.

Tsutomu Mabuchi

My Feedback: (1)

I left the choke valve as it was.
I manipulate the choke valve with a long piano wire.
It seems we had better use choke valve to draw fuel
even we use an electric starter. It seems it will make
it easier.

Tsutomu Mabuchi

finless

My Feedback: (6)

Thanks Travis, I will try that. I guess that changes as the engine breaks in? I had the L mixture pretty rich initially.

Bob

finless

My Feedback: (6)

Well I have discovered a new problem (maybe) and I am wondering if anyone else has noticed this or would check it the next time they fly.

I was flying last Sunday and it was about 95 degrees ambient. I started to noticed a different noise from the motor and landed as I thought the muffler was coming loose again. This was not the case but what I did notice was a lot of slop in the front bearing. If I grabbed the spinner I could wiggle it up and down (not end play but side to side / up and down movement). As the motor cooled down this went away.

I don't have a temperature gun but I guess I have to buy one and make sure it is not running too hot causing the case to expand around the front bearing. What concerns me is if it gets that loose the bearing my spin in the case and ruin the case!

Can you others check after a flight if you notice any lateral movement like this? Do this test right after you land. I would like to know if "some" movement is expected or normal for everyone?

Thanks,
Bob

BlueMax3

My Feedback: (1)

Bob,

I have not observed the lateral movement that you described. I ran it yesterday and specifically checked for it after running. Perhaps a call to RCShowcase or copying this post to the RCShowcase distributor forum would be helpful. They seem very willing to discuss issues like this and may know something about it.

Travis

Hirobocool

I have a Cessna 1/5 of hangar 9, with a broken motor 25, when stick this in half present a fault, []so that that fault (1/2 stick soun bu buuu bu buuu) jajajaja [&:]

thank.

Jose.

Vegabond

HUH? :-)

Fredde1

anyone that have tried a 3 blade propp, will 16/6 or 17/6 be good?

BlueMax3

My Feedback: (1)

Hi,

I tried a Master Airscrew 16x8 and it seemed to be in the right rpm range after adjusting the carb settings, but it didn't pull the plane very fast.

Travis

finless

My Feedback: (6)

DARN DARN DARN.....
Well my Hanger 9 1.50 P-51 is history!
The guy I bought it from did not secure the servo extensions for the ailerons and I lost an aileron servo. When I bought it from him I had to go over everything (lots of mistakes like no locktite, clevises not secured, etc) but one thing I did not do was to pull the servos and check that the extensions were secured. Lesson learned :-(
I was in a dive with low throttle and when I pulled out the P-51 snapped to the right. I recovered and it snapped again and crashed.
This is the most bummed I have ever been about loosing an airplane in 30 years!

BlueMax3, I am devastated as I loved this plane with the roto25. Flew great, was fast, and was the coolest looking plank I have owned yet! The Roto came out of it in good shape as it did not crash straight in. The Roto will fly again.

The bummer is you can’t get this H9 1.50 P-51 anymore as Hanger 9 discontinued the model. I would really like to replace it.
If anyone sees one in LHS please let me know so I can call them and buy it!!!

If I can't replace it, any suggestions for a warbird for the Roto? I have checked Tower and a few other manufacturers and can't seem to find a warbird suited for the roto25? Seems like a .90 - 1.20 sized bird is too small and everything else seems to want a 50cc gas engine. Any recommendations for a new warbird for this Roto 25?

Bob

Richard L.

My Feedback: (24)

Bob, the CMP Hellcat is a good candidate for your Roto 25. That plane flies just as nice as your H9 1.50 Mustang. Another warbird for the Roto 25 is the KMP Hurricane.

cadconversions

My Feedback: (21)

Also check out the new Hangar 9 1.50 Razorback. Looks great and should be the ticket for the roto 25 / 35vi. Oleo retracts too!

finless

My Feedback: (6)

Richard,
I did a google search for these and did not find much except a thread on RCU about the hurricane. Where do you get the hurricane or hellcat?

Thanks,
Bob