drac1

My Feedback: (4)

Hey Matt,

I never had the need to fiddle with glow

MTK

Ohhhh....you're the one!!

drac1

My Feedback: (4)

Lol

drac1

My Feedback: (4)

Hey Dave,

It would be good to catch up at a comp sometime. My next one in Australia is Horsham.

You going to that one?

Uncas

My Feedback: (1)

Does the DLE really need a tuned pipe? I would like to try this on my Temptation.

marrinersgarage

Hi Scott, not sure if I can make it to Horsham but see what happens

Uncas, I've not run the DLE without a pipe, my guess is it would be ok if the plane is not too heavy and its not too windy but might be a bit noisier

papaone

Hello

Engine is PTE 36 R so there is no problems without tuned pipe, just a little noisy with muffler.
http://www.troybuiltmodels.com/items/PTE36R.html

MTK

The DLE35 has enough power to fly a 10lb airplane on muffler. You will need a smaller prop, something around 18.1x10 or so for similar rpm as with pipe and larger prop. I played a little with canisters from ESComposites a couple years ago and the DLE did fine. A temptation shouldn't weigh much more than that, right? Consider that that was state of the art just a half dozen years ago with the OS140RX and Webra 145/160. My Temptress (Temptation with my own design wings/stabs) was Webra 145/160 and OS140RX powered at one time or another. Weight was mid 9's back then, but picked up a few ounces after converting to gas 4 years ago.

But still, for best output, a full tuned pipe produces better RPM and considerably more torque. Then you would be flying at mid stick for the whole flight meaning you have a lot of stick left for anything else you want to do.

marrinersgarage

just a little more info on the soft mount. Whilst we pretty much followed Matt's method on the soft mount construction we couldn't find an inner tube of suitable diameter so instead simply overlapped a single layer of rubber using a belt sander to create a nice clean angled join using Loctite Black Max rubberised CA adhesive. No signs of any deterioration on this joint so far.

Uncas

My Feedback: (1)

I have a tuned pipe on my OS1.60. It was a bit of a pain to tune it. Once it is set I guess it is okay, but I was hoping to get away from it.

Also, could you have just bought a Hyde mount?

marrinersgarage

I don't think the tuned pipe would be essential. Even though I don't think we have the tuning optimised yet I haven't found it to be overly sensitive, its pretty light and keeps the noise down (nowhere near as quiet as Scott's YS though!)

You could certainly buy a genuine Hyde mount and I did talk to Merle about getting one but unfortunately the size wouldn't fit in the space we had to work with and the price didn't fit into my budget. I cant compare the one we made to the genuine Hyde but it does seem to be working ok so far and made a noticeable difference compared to hard mounting.

Alternatively you could look at something like the isolation mounts shown in Claude's post on the previous page, we will probably try one of those setups in the future but had trouble sourcing the bushes during this build, I believe now the ones we were looking at are back in production.

MTK

Let me suggest you cut yourself some slack. Hyde has been custom building rubber iso mounts for 25+ years. I'd veture a guess and say he's built 20,000 over the years (making him a millionaire which is great for him). The one you built was number 1. Just like I've done, you will learn new ways to make then, making them lighter and stronger, and balance them for best performance.

In regard to noise, let me suggest that you soft mount the pipe also. I use a single Lord type mount for the soft mount base. I've posted how that's done on the various threads I've contributed to.

In my latest design, Delta, I've lined the chin with some soft foam and surrounded the engine intake with soft foam to further suppress noise. It all helps and it just depends on your threshold for how far you want to take noise suppression. Delta is exceedingly quiet, at least on par with any 2 or 4 stroke of similar size flying pattern today. About as quiet as most electrics in reality. Practically anything else flying drowns me out

marrinersgarage

I wasn't suggesting our mount is inferior, its just that I've never actually seen a Hyde mount in use so I have nothing to compare it to. I've been more than happy with its performance so far and I think the total materials cost was less than $20.

The noise level likewise has not raised any concerns at any of the competitions I've attended so far and its not a huge priority for me to improve it further at this stage but its good to hear the ideas on how it might be improved in the future. Compared to the old Enya 40 I mounted on the trainer last week it is whisper quiet!

marrinersgarage

Just an update on the DLE, have put a few more hours on it and the engine seems to be running in nicely now and I can fly an easy two schedules, land, refuel half the tank and one flip and its running again so more than happy with that. Still running standard unleaded fuel (91 octane) and coolpower blue oil at 32:1, it hasn't caused any issues so I haven't seen any need to mess with it.

I got one of the local gurus to have a fly on the weekend and he put it through the F3A schedule and the main things I noticed were that he used much less throttle than I do and still seemed to have plenty of power in reserve for all maneuvers. It was a pretty calm day but I think there would be plenty of power available if it got windy and no concerns of running out of fuel. Still going to try lengthening the pipe but that is more a case of wanting to shift the powerband a little lower and gain a little more torque for pulling over the top of the loops.

All up I think its going pretty well so far.

drac1

My Feedback: (4)

Sounds like you are pretty close to having it all sorted.

Good throttle management is a must for F3A.

apereira

Hello guys,

I was just reading the old posts and noted the kill switch accidentally being activated in flight, may I suggest you guys make a logic mix so unless the throttle is at idle the kill sw will not work?, this is the same as the throttle cut but on a on/off channel activation separate from the throttle.

Regards

marrinersgarage

so at the contest last weekend I was noticeably struggling with power in the up lines with the engine running a bit rough. I don't think we've changed anything and all I can come up with is that with spring arriving it was a little warmer and drier than it has been for a while and possibly its running a bit rich and with the pipe length being a bit short it was struggling to get 'on the pipe'.

Any suggestions?

MTK

Yes, I have a couple, having run this engine in an 11 lb Vanquish several years ago except mine wasn't piped. Ran a 19x10 Xoar wood laminate prop with my standard fuel (avgas and 50:1 synthetic oil) on a non-tuned cannister. It produced good enough power for the Vanquish in all conditions so the engine, at least my copy, developed the required ponies even on the can. It produces a bit more piped.

I've run all of my GT33's piped so I have experience with piped set-ups.

If the pipe is short, lengthen it to appropriate length. I've found that all of the 30-40cc gas engines that I have run respond well to a length of 27" from the plug to the reflector baffle. I've run longer lengths too, to 30" with negligible effects/improvements.

Warmer temperatures reduce gas engine output except we're talking temperatures in the 90's. From the 40's to the 70's, there's minimal difference; in the 80's there's a small delta and in the 90's the delta is a bit greater (lower output). I didn't have to adjust the needles cooler to warmer until temps went to the 90's and above; it is quite different than glow. If you had yours too fat to begin with, then leaning to appropriate mixture is a must. Petrol operation is different than glow in that it buys nothing to run the engine fat. Timed ignition doesn't depend on mixture to fire right.

Take a look at the plug; if it was running fat, it will have a darker (black) sooty, wetter appearance. You are looking for a light tan, dry looking color. Grey ash is lean.

Proper cooling requires some ducting. My ducts are thin 1/16" but firm foam rubber sheet. It is firm but flexible enough to conform to the engine's fins. They actually touch the fins in places. They are ca'd to the chin cowl. They steer the ram air directly over the fins of cylinder and head. This is proven in the hottest and most humid of conditions to work well no matter how extended the vertical. Thin fiberglass, depron, 1/32" balsa sheet, all work fine. Some attention is also required in the air exits. I really like and recommend some type of louver on the leading edge of the exit area (I use hooded exits) to draw the hot air out. Look in my Derivative thread pictures to see the treatment I use successfully.

Good luck

marrinersgarage

Thanks Matt, had another look and found the exhaust joiner had split. Replaced that and richened it up a tiny bit on the high speed needle and its back to running as well as it ever did and happy to climb out of sight. The weather wasn't really that hot only mid 20's celsius (or mid 70's farenheit). Still going to have a go at lengthening the exhaust and see if that helps but it was quite good to fly today.

Matt I've had trouble locating any of that ceramic sleeving you used in your joiners here in Australia, any chance I could buy some from you?

Cheers,

Dave

MTK

Dave, shipping cost could be prohibitive to Australia. The unit cost is 10$ each plus S+H.

On the other hand these things have proven themselves over 100's of flights and simply don't seem to wear or burn out so as a one time purchase it might be worth it to you. I would need to know the exact diameters of the header and the pipe. Couplers are custom molded.

On a different hand, try molding your own from 6 ounce fiberglass. Impregnate the glass with Permatex Ultra Copper and simply roll the glass sheet around the pipe stem. Wrap it securely with some food wrap film to hold it while the Ultra Copper cures, then remove the film. Try it and see how it behaves. You want at least 3 layers of fiberglass because the innermost layer will likely char from the exhaust. The glass will work easier if it is bias cut (cut at a 45 deg angle)

Good luck

marrinersgarage

Just another update. Finally got around to lengthening the pipe a little and its now lost the slightly rough running at low rpm and runs clean now all the way through the top end. Its lost about 700rpm off the top end but its not required and no longer exhibits any real 'peaky' behaviour. The torque curve has improved as well and it will now happily accelerate after a long climb to power over the top of a loop. Am in the process of making up a new longer header to try it a few more inches and see the difference but I think its pretty close now.

marrinersgarage

Another quick update and unfortunately a sad end to the story. We had a massive bushfire go through South Australia this week and unfortunately it took out the shed at my Dad's place that housed all the models, including the Integral, so it is no more (luckily Mum and Dad got out and their house is ok).

We had plans to work on weight reduction, pipe length changes and prop testing over the christmas break which I think would have lead to improved performance for 2016 but for now at least the experiment is over.

Dave.

MTK

Dave, that's terrible news. I'm sorry to hear of your loss and your dad's. It should be covered by homeowners insurance I guess. A fire that close to home has to be devastating.

Hopefully you can replace and rebuild. When you do, you should consider upgrading to the OS GT33 primarily because of its low end grunt with larger props. This powerplant is adequate for up to at least a 12 pound plane so if yours comes in a bit heavy, no big deal really. Of course it assumes that nobody weighs at your comps.