MTK

Yep, it's the new DLE55. One of a kind prototype with extreme measures taken to lighten it up. Here are some more pics

MTK

Some of the lightening measures:
Round head, drilled fins, 1/3 thinner mounting lugs, from 10 mm down to 7mm. Plenty of strength there especially since the engine is being soft mounted.
Drilled prop hub; titanium bolts all around except exhaust and prop. Wanted to also use a single nut style prop attachment but the only thing available from ValleyViewRC was much too heavy.

Stand offs were replaced with a set from Syssa Aircraft. Designed to use 8-32 bolts rather than the 10-32 or 5mm the engine comes with. A soft mounted set-up doesn't need anything more than that, and even that is overkill.... 6-32 would have been enough.

Anyway, reduced the weight by nearly 5 ozs, down to less than 43 ounces for engine only. Unfortunately had to use the original, heavy 50mm x 5mm prop attachment bolts. There's more weight savings there with titanium but I just couldn't justify an additional 50$ for 4 bolts.

MTK

A couple more pics of the cowl treatment....I don't think one can cool a gassie enough. The baffle is 1/32" balsa, glassed in place. Turned out to work much better than I thought it would. Easy installation

The header is the typical stainless steel variety one can get from the DA website. Had to buy the parts from Germany and assemble them for the lightest and snuggest fit around the cylinder. The RTC Header weight is about 15 grams heavier than a side aluminum header from Macs. Brazing knowledge is a must to work with stainless thin walled tubing

MTK

Ran the engine today.....quite impressive output on the pipe. 22x12 MDK Hybrid prop turning in the low 7s. Thrust to burn. Quite likely 3:1 ratio of thrust to weight. If the weather holds, I will try to get a maiden flight tomorrow. Need to run this thing to hopefully break it in before the snow flies

BTW- the DLE started right up using the stock DLE spark plug. I have the CM6 plug in my flight box, JIC. Oh yeah, the fuel is avgas, 50:1 gas to oil, Bel Ray MC1 racing oil

MTK

TaRTS,

How did this set-up work in your plane?

What prop are you turning on the DLE30 cc?

tarts

I haven't seen a hyde mounted gasoline engine running so I can't compare. The wings are still vibrating, but I could see the motor moving and dampening the hits. The first grommet material I used was foam-like rubber, that worked good but wore out after a while. Now I made them out of silicone and it's holding up pretty well although the material is a little too hard and not so flexible. Overall the system works and seems solid.

I'm using Hawk 18x8. I used the same prop for breaking in. It suits good with my flying style pattern and 3D mix. I gave tried 18x10 and 19x8 but the motor overheated. I think I need to retune the carb for new prop. But as it woks good and carb is also set up really good (I think) I won't touch it. Im only a little worried about too high RPM that may damage the engine in long term. Is there a reason to worry?

MTK

The Hyde style mount I'm using dampens the high freq movement and vibration but still allows the wing panels to move, at a much lower frequency.

I am curious about the prop because the SAP tends to overheat as I go to higher pitch on 18" and larger props. I've been using a 17x12 then switched to a 16x12 and the engine was happier. I've run it with a 19x8, piped, and the engine was still okay but it seems happiest running the 16x12 on pipe.

I've heard that the DLE hauls a bit more lumber than the SAP but it looks like in your experience that's probably not true

The 55 hauls the 22x12 with great authority on the ground. I am very curious how it will do in the air. The soft mount appears to control vibration to the airframe fairly well, even on this very lightly built model. But let me get a couple hundred flights on the set-up and then see how the model fares

tarts

We have 3 DLE30-s on the field(including me), one with 18x10 and other with 19x8. The guy who runs 19x8 has never touched any needles and it still has this rich factory setting, running without any problems.

MTK

I've got 6 flights and 8 tankfuls through the engine so far, almost a gallon. First impressions, very powerful set-up turning the 22x12 hybrid prop. Fairly quiet for the displacement...in other words too noisy by pattern standards. Pipe works well in boost.

My soft mount is a bit too hard....too much rubber. More airframe shake than I want. But it's plenty strong enough. Will build another to soften it a bit more. So you can soft mount a 55cc gassie on pipe. Experiment answered that question.

I am finding thatthe EF extra just won't hold a line. Drifting in every axis. It's gotta be the Spektrum servos. With a 55cc up front a bit more tork won't hurt. It's probably too much power for the airframe and with the huge aerodynamic countebalances on the control surfaces, the servos are likely compromised. I think I'll go back to JR all around and up the power a bit.

Also will be trying a 20x12 3 blade to tone down the rpm a bit. The 22x12 2 blade rips the air pretty well and is a bit noisy in the air.

There is no final word on this experiment yet. The light airframe is holding up which is very good and speaks well of the factory builders that built the plane. Also speaks well for the mechanical design of the crate

MTK

I've got about 1 1/2 gallons (3 gallons total now) through the engine with the 20x12 3 blader up front. It's standard Mezjlik 20x12 3 blade. The DLE is now beginning to show signs of full break in and I need to fully lean it out, both HS and LS needles. The DLE and 3 blader combo is simply outstanding. It is super quiet just like an electric at any power setting except full throttle when you can hear the reeds a little. Anything else flying at the same time including some 40 size trainers judging from yesterday's flying, drowns me out. The Mezjlik 3 blader has made that much difference in the noise generated. Downline brakes have to be observed to be believed. Powerwise, it's a nonissue...the plane is only 13 pounds afterall, so how much thrust does it really need?

I've been flying masters pattern sequence at half throttle including all the extended vertical stuff. Really neat stuff. I currently have an 18 oz tank in it and I can fly 2 sequences back to back and have about 1/4 tank left over. The Extra is not the most precise bird out there but boy is it a lot of fun to fly now with the power set-up I have. There is nothing magical about the set-up either meaning anybody can duplicate it. The soft mount is the sole exception but Merle Hyde would likely make a soft mount for the DLE55cc.

MTK

I am satisfied with the DLE55 experiment. This one worked out better than expected. With a 20x12 Mezj 3 blader, it was outstanding in all aspects

The Extra was outfitted with a new Mintor 38 cc with a 40G pipe from ES. During the Mintor's maiden flight something went wrong with the radio. Lost the link on the vertical downline of a turnaround humpty, immediately following the half roll. I was at about 1/3 throttle as I was setting up for my pull to level flight.

The plane hit hard in farmer field dirt so I hope the engine could be salvaged. I have the pieces on the bench and will be doing a post mortem soon. Not much left tho. It was as beautiful a crash as I've ever had

tarts

Sorry to hear about your loss. Would it be possible to determine what caused the signal loss?

MTK

The receiver probably went south. That was a Spektrum 9000 RX purchased in a 2 for 1 deal from Horizon a couple years ago. I had a problem with short range before with it. After Horizon returned it from new software last year, I had put about 75 flights on it before the crash.

At first it seemed that it may have been the battery coming loose. Except I use a Battery Eliminator for my CDI module which means I have only the radio battery driving everything. If the battery was lost I should have lost ignition.....I didn't

swk550

My Feedback: (76)

Matt,

Sorry to hear about your loss. I am in the final stages of building the same airplane (red version) using the Mintor 38cc, ES Composites ES40G pipe and a home made isolator mount. Thanks for the advice on making the mounts. It's been some five plus years since I made the last monut for a OS140 rear exhaust engine. I'd like to keep the build thread going, so I am posting some pictures of my set up. The mount ended up being 4.124" diameter, 1.06" thick. I cut the firewall back 0.25 too much, so I had to add 0.25 spacers for the standard 3" long Mintor standoffs.

SWK550

MTK

Thanks Steve, no biggie really. That's the good thing about ARFies....somebody else did the work so no emotional ties to it.

As it turned out the Mintor burried a foot deep in farmer dirt. Reasonably soft in other words. Great thing about a rear mounted carb, no crap inside the engine. Just a few bent fins easily straightened and a quick run under the faucet had the engine looking like new. The hit pushed the shaft back a bit so I removed the carb/reed block and rapped the shaft back into position. It looks like the whole thing was saved. Tough little engine

Your mount looks great. It will work fine. I build mine with studs through the face that stand offs could be screwed onto from the front. This way I can mount the donut on the firewall first. BTW, I had put in a choke servo in my set-up. I have photos in the OS33GT for Pattern thread

Speaking stand offs, mine were standard McMaster Carr issue, 2 1/2" long. I turned them down from 3/8" to 5/16" to shave some weight. These were about half the weight of the stock stand offs. After the hard hit I expected them to look like pretzels. Well, there wasn't a scratch on them which tells me that the usual stand offfs one gets with the engines are way overbuilt. The soft mount is another story...completely destroyed; soft enough to have probably saved the engine

swk550

My Feedback: (76)

I hope to run the Mintor 38cc engine today. If all goes well, I'll test fly the airplane. I did install a choke servo. I am waiting on the Mintor exhaust header. After I get one, then I'll finish the ES40G pipe installation.

swk550

My Feedback: (76)

Some more pictures

MTK

Do you know about the Tech Aero IBEC and regulator? These are terrific electronic devices that reduce weight and allow using your TX as the ON-OFF switch for the CDI.

captinjohn

If you want faster break-in and better runing...install a Frank Bowman piston ring. Capt,n

captinjohn

If you seen the photo why most people do not run the stock DLE sparkplug...I think you would throw it away! The center post starts rusting real bad under the white insulater. Capt,n

tarts

I agree. I discovered that a piece of ceramic was missing from the inside of the original plug. I hope the piece didn't get stuck anywhere on the way out. Replaced it with NGK and most of the problems(missing beats) went away.

tele1974

Interesting thread. After my first IMAC contest last year I installed a ZDZ 50NG in my Extra. I didn't get many flights on it. But, after learning how to start the ZDZ successfully. It ran flawlessly. I would like to install a ES40 pipe. Not that it needs any more power, I would like to decrease the decibels. I won't have any problem getting over the humpty bump into the wind now. MTK, great job with the baffling.

MTK

Thank you Patrick.

I finally got around to taking the pieces totally apart to inspect. Considerable radio damage unfortunately. The IBEC and voltage reg and a couple servos were broken. But the engine, header and carbon pipe came through in good shape. I needed to re=bend the header a bit that was all. The surprise was the pipe....it's all carbon after all and weighs a scant 3 1/2 ozs. Ed Skorepa has a fine product there.

The original tank supplied with the plane is good for either glow or gas. The stopper held up to avgas, np. But the tank didn't fare so well in the crash....bent around 45 degrees in the center, LOL. Wing joiner was broken in half....impressive. Stab tube and the tail group came through unscathed

This plane is built supremely lightly, yet it held up fine to the soft mounted DLE55. Couple lessons from this: most other planes are way overbuilt; soft mounting works great even on light airframes. Of course they get truly crunched when they hit the ground.

TimBle

nice work.

MTK

Thank you....I did a great job crashing the beastie. It was one of the greatest, most spectacular crashes I've seen LOL. The only thing that would have made it even more spectacular would have been a fire. Came close with the lipo battery being bent like a pretzel but no dice!

The Mintor was simply cleaned up and put back into service. Didn't even have to take it apart. The engine is built extremely strong; afterall it is all machined bar stock aircraft aluminum. I seriously doubt that any cast engine would have come through unscathed as this one did.