Dub Jett Engines Support Bob Brassel of Dub Jett Engines provides direct support here for Jett Engines.

Bse ro-jet .25

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Old 04-28-2015, 03:01 PM
  #1
dbacque
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Default Bse ro-jet .25

Bob,

I received a BSE RO-JETT .25 engine from a late friend a while back and I'm wondering a few things about it. From what I see on your web site, the RO-JET is a C/L engine. This one is clearly engraved RO-JETT but it has the red carburetor. Were any of these engines produced in this configuration or is this something the previous owner may have done? The barrel in the carb has a narrow slot in it compared to the full diameter holes in the carbs on my .40 and .46 Jetts. So I assume it's the right carb.

I made one short test run on the engine with a 9x5 APC. It held at 16,900 and peaked at 17k. It was a very brief run and I did not try to see where it would hold or if it would peak higher since these numbers seemed to match what I saw on your site. I know the engine has been previously run but it is so clean that I wonder if it's ever been flown. There is no serial number on the engine.

Basically, I'm trying to find out the difference between the RO-JETT and your other engines, and how this engine will perform in its current configuration. My brief test said it ran great! But do I need to treat it differently from my other Jetts? Does it want to be richer or can I tweak the needle like my other Jetts? I have it targeted for a zippy little RC plane and expect good things. I've still got the 9x5 on it but of course, I'll try other props once the thing is flying. I'm going to start running the engine soon and just want to be sure I treat it correctly.

This is for purely sport, but going to be fast sport.

This engine has baffled me since I inherited it since it doesn't look like anything on your site. It sure runs great and throttles nicely!

Thanks for your support,
Dave

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Old 04-29-2015, 11:19 AM
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Not that it helps you much, but I have one like that too. It's a BSE 25, AAC setup, with the red carb, slotted barrel.. and it also has "RO" machined into the side of it.

I haven't run mine yet - bought it used, and while the piston/sleeve fit is still pretty good, the bottom end of the rod was bad, had a crack in it. Just put a new rod in it, haven't run it yet.

I'm thinking that someday I'll build a "Das Liddle Stik" for it. Can't put that machined little jewel in a cowling!
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Old 05-14-2015, 10:08 AM
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Hi, and again all.. sorry for the delays..

The Ro-Jett markings were from the crank case manufacture phase. If you have the RC carb, it is a regular BSE .25 engine Dub makes the parts for Ro-Jett control line engines at the same time.

Nothing special about it, and yes run it like any other Jett engine. The 9x5 or 8x8 prop is a good choice, let it turn up a bit. Set the mixture down about 800 from peak rpm and it will be happy.

The RO-JETT engines for stunt are still available. Mostly the "25" size block engines are sold as "35" or "40" engines. The "40" size blocks are configured as "65" or "67" size engines.
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Old 10-20-2015, 02:35 PM
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Hi Bob,

Yep, that's the engine I'm flying and it's a little screamer. I'm having a ball with it. It's on a Sig Wonder and wow, does that thing go!

I've been flying it for months but suddenly in the last 3 weekends, I've broken 3 muffler bolts. Always the front bolt. Removal isn't always easy.

I've double and triple checked my prop balance and according to my DuBro balancer, it's dead on. Everything is fine before the flight. The plane makes several uneventful flights. Everything is still fine when it is launched, then 2 or 3 minutes into the flight the engine sputters and dies. I land and find the muffler hanging by the rear muffler bolt.

Months of flying with no problems and now it's 3 bolts in 3 weekends, each after about 3 or 4 flights.

It makes no sense to me. Everything is bolted down tight with new bolts every time. Nothing is over torqued. Everything is Loctite'd. And after 3 flights the forward muffler bolt shears between the engine and the muffler.

Is this a problem others have seen? Any suggestions on how to deal with it?

Thanks,
Dave
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Old 10-30-2015, 09:59 AM
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Hi ... Thanks for writing, and sorry for the delay replying...

You have to ask yourself -- "What changed". If it is breaking the front bolt, it is shaking

Usually if it is breaking the rear bolt -- that is more a bearing going bad.

My suggestion --- make sure the prop-stud is not "tight". It should be installed all the way in, and then backed out about two turns. It should slightly float.

The prop drive is the "square" mechanisim, and the prop nut retains the prop.

If you tighten the prop stud all the way and it bottoms out hard -- it will deflect ever so slightly to the side. That could cause your prop to mis-align and create that shaking.

Check on that, and see if it helps

Bob
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Old 10-30-2015, 04:34 PM
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Yep, I seat the prop stud and then back it out a couple of turns. This happened 3 weekends in a row. Never happened before and hasn't happened since. But that's only been one weekend with lots of flying.

Thanks for your thoughts. We'll have to see if it happens again.

Dave
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