Doomking

My Feedback: (38)

Jim you are correct
It is a Bennet muffler.
The only concerns that I have with mine since it is brand new and has not been installed yet, is one of the comments that someone made few post earlier about the diameter of the Bennet exaust staks being somewhat smaller than the stock one and therefore more restrictive.
Any comments you can make on that Jim with the one you are using?

sbrackets

Hey Doomking

Don't be afraid of what you hear. This muffler from Bennet is jam up. We have not seen any loss of power due to this muffler, Only a deeper sound. Bennett Mufflers have been around for a long time. I'm sure Denny knows what he's doing when he builds a muffler. That's what he does!!! You'll be fine with the Bennett muffler.

Jim

JoeMamma

Due to my club's db noise rule, I will need an actual muffler and not just an exhaust diverter.

The first thing I'm looking for, whether it be a JTEC, Bisson, Bennet or any other brand, is if it's truly a muffler.

I'm really jealous of you fellahs that don't have db noise rules..........must be nice.

Joe M.

thepamster

The only "truly" mufflers I have ever seen sold with gas model airplane engines were the ones that came with Zenoah engines. The were fat and bulky but were actual mufflers. All others, with the exceptions of canisters, are exactly that, exhaust diverters.
Try searching for something called "Snufflers", which you attached at the end of the pipes on your mufflers. I can't remember who made them. It could even have been Bennett.

JoeMamma

Thanks pamster......I had never heard of Snufflers......JTEC carries them http://www.jtecrc.com/snufflermufflers.htm

Looks like if I order a JTEC muffler for my 55RA they will need to do a custom installation on a pair of these Snufflers.

I'll be giving them a call.

Thanks Again,
Joe M.

Michel

Hi

Yep ,........... I cut off a little over an inch . ( please check youre exhaust port on the muffler when you get it )

Michel

JoeMamma

Just talked to JTEC. He completely talked me out of getting a DLE 55RA instead of the side exhaust DLE 55. We discussed the reasons why for a while, including why DLE even went to rear port exhaust.

His reasons sounded pretty good to me. He also told me by using the side exhaust 55 there are many more muffler options available by almost all of the muffler manufacturers.

After I get the DLE55 mounted, he said to take some pictures and get some measurements. They will then custom make anything I want. They can get the down tubes to exit anywhere I like with or without the additional Snufflers. We also discussed db noise rules and the use of certain 2-blade props to help curtail noise when using the DLE55.

I learned a lot and the phone call was well worth the time spent.

Joe M.

Sonny.C

My Feedback: (23)

And the reasons explained why DLE went to rear port exhaust are?

JoeMamma

The biggest reason JTEC could think of for going to a rear port design on the RA was to be able to fit the exhaust behind the engine instead of cutting another nasty hole in the side of the cowl for a side mount exhaust. The DLE 55RA would be mostly for planes with smaller cowls. I won't have that problem with my particular plane as my cowl is approximately a foot in diameter.

Joe M.

Michel

Hi

WarBirds baby ,..................................pure and simple ,WarBirds

Michel

thepamster

One think to watch out for with wrap around type mufflers is they can come loose if you don't put a brace on the rear part for support. Some come with a threaded attachment for this purpose.

Doomking

My Feedback: (38)

Thank you Jim for the reply.
I will go ahead then and use the Bennet muffler with my RA in my p-51.
Thanks again.
Fabio

Michel

Hi

I can imagine youre P-51 is a TF BBD ,...................... do you have an all up weight ?
Michel

JoeMamma

Thanks. I tried everything I could to prevent the muffler bolts from coming loose during flight on my O.S. GT33 gasser. Different types and brands of Locktite, etc., etc., homemade gaskets, etc., etc. I DID find out they make an ultra high temp thread bolt locker........good for up to 2000 degree F from what I remember. I also remember it was around $100 for a small bottle. It was NASA approved so that's probably why it was around 100 bucks.[X(]

The muffler problem was driving me nuts........very annoying. Plus I was buying exhaust gaskets two at a time just to keep them in my personnal stock.

To finally repair it I replaced the supplied 5mm allen headed muffler bolts with 5mm grade-8 studs threaded at each end (a stud is ALWAYS stronger than a bolt). I also got a set of crimp-type grade-6 nuts. At the end of the outlet down tube I made a support bracket. I now have about 50 flights on the same engine and everything is still tight.

After finding out a number of fellahs had the same muffler problem on this particular engine, I also found out (sadly) O.S. would not admit to any exhaust problem.[:@]

Joe M.

Michel

Hi

This is an MT-57 , with Sullivan , a smoke inverted pitts . It stays there .

Michel

thepamster

Sometimes the gaskets themselves can cause issues as they can expand and contract and work the muffler loose. I no longer use gaskets on any mufflers and use a gasket sealer instead.
The "red" type of thread locker is high temp stuff available at auto parts stores and is under 10.00 a tube.

Glad you got it fixed Joe. Now you can fly with piece of mind.

thepamster

Yep, you can see the support on the rear. It is bolted to theengine and "not" the firewall. It needs to vibrate and flex along with the engine.

MTK

No reason at all for 55cc engines to sound like chain saws.... Here's my slightly reworked DLE55 side dumper. Wished to heck I had the rear exhaust DLE55 when I was setting the engine up in this design

Here is my solution: Piped and rubber iso mounted plus a really quiet 20x12 3 blade Mezjlik. The combination is whisper quiet. We will be video-ing the model to show its quiet gentle manners.

I attach any exhaust set-up simply by adding a thin layer of Permatex Ultra Copper hi temp sealant to flage and bolts. I also use the stuff to make my own coupling stock or exhaust stingers from ceramic

Take a look at the plug treatment.I always discard the springclip in favor of short length silicone rubber. It holds great but gives when I want it to

NJRCFLYER2

My Feedback: (42)

Looks great Matt! When is the maiden flight?

JoeMamma

MTK,

Your solution looks nice. You are correct about using a pipe to get her quiet. That always works.

From your pictures I can see why DLE went to rear port exhaust on their 55RA version..........no more bulge on the side of the cowl on smaller-cowled engines.

For my application I simply can’t use a pipe to quiet her down...........at least not without a major teardown and rebuild of the lower front end.

I picked up a Troy Built a 107” Cessna 195 Businessliner https://www.troybuiltmodels.com/item...95-107AAF.html

I trying to achieve as much of a scale look as possible. When it comes to scale looks, the exhaust/muffler usually always presents a problem.

Because my cowl is almost a foot in diameter, I can easily get almost any exhaust/muffler within the cowl using the older side port DLE55. But, the cowl on this particular plane is short........a little less than 7 inches. Because the cowl is short, the rear exhaust DLE 55RA would be more difficult to install than the side port 55. If you go back a few posts, I explained why I’m going to use the older 55. After talking to JTEC, I have decided to have them custom-build me a scale-like exhaust and muffler.

PS: The picture is of the look I’m trying to achieve.[8D]

Joe M.

MTK

Ed,
Maidened Delta today. It performs well! The theory I discussed early in the Pattern thread proved to be on the mark....no roll couple and only a slight hint of pitch couple. But enough of that in this thread.

JoeMamma, a pipe is only one small piece of the noise puzzle.....not the most important piece. Engine rubber isolation from the airframe and a quiet 3 blade prop are even more important. I use a Mezjlik 20x12 (3Bld) carbon, which is far quieter than a 22x12 2 bladed prop for example

There are canisters that exhaust on the front end of the can and could give you the scale look you're after. Canisters could produce a noise improvement for you; but I wouldn't expect miracles.

If you are really serious about noise reduction, contact me directly at my email in my signature. Solutionsfor noise abatement are not cheap but are very worthwhile. I would bet your model would sound terrific with the things I do ......

JoeMamma

Thanks for the offer Matt.

I've talked to fellahs using 3-blader's. Yeah....a definite sound benefit using one, but for scale I will need a 2-blader for this particular aircraft.

I just started to investigate rubber insulation.

Thanks Again, Joe M.

brunobortesi

The DLE 55 RA engine runs great. I have it in an Aeroworks 50 cc Ultimate. The power is perfect for that plane. THe only minor issues have been vibration and after the break in period, the carburator was very dirty so it would not start. I do believe that the DA 60 is the better option and it is worth the money.

Truckracer

My Feedback: (19)

Curious, what was dirty in the carb and what was the cause? I guess I don't understand what would be different between a DA and a DLE when it comes to the carb being dirty if you were trying to make a comparison there.

wjcalhoun

Hi Guys
This thread is a bit old, but I think it the correct place to post the question.
I have a DLE55RA installed in a Revolver 90. Jtec muffler. The engine has about 4.5 gallons of gas through it - 3 gallons of 1:32 Pennzoil aircooled, and the last 1.5 gallons Stihl Ultra HP 1:40. After 3 gallons I installed a Frank Bowman ring. I estimate about 6 hours of run time - 4 flying and 2 on the ground for setup, tuning, etc.

I was flying today and during a roll inverted, the RPM sagged a bit, which recovered on rolling upright. Two minutes later, during a large loop, having just crossed the top, the engine sagged again, and died. Uneventful deadstick landing. I figured that it was a carb tuning issue. But, when I turned the prop over there was very little compression, whereas before the engine had great compression. I pulled the cylinder tonight to find a score on the piston, from the top nearly down to the bottom of the skirt. The ring groove had been squeezed tight against the ring, but the ring is not broken (see photo). The score on the piston is between where the exhaust port and transfer ports are placed in the cylinder. The cylinder has a mark at the corresponding spot, but it feels mirror smooth (see photo). Conrod bearings top and bottom seem OK. The main bearings are glass smooth and have no play.




It seems to me that something entered the cylinder from the top. Might this have been debris through the carb? Might a small piece of dirt fallen back into the exhaust port from the muffler? I never had anything like this happen before in 5 years of flying.

I think the piston is done; with the deep score and peened ring groove, it is beyond my skills to fix it. The ring might be salvageable. The DLE55RA piston is $45, while the DLE55 piston is $15. Any ideas why that is?
I am not planning to replace the cylinder, as it has no detectable imperfections.

Any advice from the engine gurus?

Thanks in advance