I don't buy (or care about) DA, and I enjoy flying for the hell of it. Have absolutely nothing to prove by competing. So I guess as a "sport flyer" I know nothing about tuning, set up, engine work, or trimming a plane.

Nothing personal, but struggling to agree the only guys that have a clue are those competing and/or flying DA.

FWIW, -Al

+1, though I use to be a very active competitor. Don't hold it against me please.

That's what I rambled about in the last sentence on post # 32. I've known some so called sport flyers that could put the experts to shame with their engine knowledge. We have a vast knowledge cross section in this hobby.

Wow, is that really what you got from what I said? Competing does not mean that I am trying to prove anything to anyone but myself. It's about pushing myself toward continuous improvement. Where did I say sport pilots know nothing about tuning or trimming? I said competition pilots take these to a higher level. Why is it every time we don't agree on something you feel the need to exaggerate and put words in my mouth?

Its been a long time since I was in the industry. The profit margins are much smaller then what people think. We would actually make more money selling an Futaba FM 7 channel radio over the first PCM radio. The high end specialty stuff was very slim margins mainly due to smaller market. Most airplane kits were priced 33% over cost, we stocked the complete Byron line and only made 25% from those kits. Granted they were high dollar kits. Some engines such as Rossi, OPS and Webra were priced 20% over cost. We made more selling an OS 25 FSR then a .90 FSR. I agree about servos, I haven't bought a Futaba servo in 20 years. But the servos I do buy are always high quality units. I have been known to buy used if in good shape. My Extra uses a combination of Hitec, JR and Savox servos simply because I had to buy a pair at a time and got what was a good deal at the time.

Speed, I thought I was done with this but ....

When competing, I learned so much from so many people! Especially when I was in my 20's. One very good friend was always very short with me but taught me so much. For everything he taught me it was always accompanied by a story about where he learned what he was forwarding on to me. He had been a product rep for a major petroleum company and had traveled and lived around the country. He had competed and befriended the very best of the time and had so much to share that he had learned from these people. It was a different time then and though some competitors were unapproachable, many others loved to share their vast knowledge. Later on in life and racing on a very limited basis, I found the same atmosphere with completely different guys in different places. Yes it was often very serious competition but in a friendly atmosphere where knowledge was freely exchanged. Likewise I remember passing on my knowledge that I had expanded when traveling to areas where the guys were less knowledgeable and the cycle continued. I'm not sure it is that way these days or not though I suspect the atmosphere still exists as people get to know each other. It was all about fun for the most part. Regardless, I see and appreciate both sides of the fence.

Not sure this has much to do with DA engines ....

Actually, I wasn't pointing my finger at anyone. You feeling guilty about something you wrote?

Merry Christmas guys!
-Al

Guys, competitors have always pushed the mfrs to design and offer better stuff. It's true in our hobby and it's true in every other endeavor were competitions are held. Nothing new there.

What im saying is that the cash cow for the mfrs has always been and will continue to be the sport fliers. The numbers simply favor this paradigm. Although I admit that in the past 10 years give or take, certain mfrs., radio makers for example, have pushed the art some. Just look at how the number of channels being offered have changed. Or look at the servos. Bottom line, everyone benefits with the choices.

im not sure what this has to do with DAs pricing either.

Are DA's worth the extra money, they sure are if you have it, spend it if it makes you feel good.But you can spend half the money and get the job done just as well and not have to buy a muffler for your new engine.The muffler thing is my biggest gripe about DA,when you spend a lot you would think you would get a complete engine.

You have to pay extra for the muffler? I have heard that before....unreal!

Great question , and real good info ,for someone purchasing a gas engine ,in the futurer

I have two DA 50's and my biggest grip is DA's use of red anodized aluminum bolts to hold the cylinder and carb on.
Both have broken off and I replaced them with good ol STEEL cap screws.

I have two DA's,the 50 that I have blew the cylinder off while in flight,the aluminum cylinder base bolts broke.They look nice but have no business holding down a cylinder.DA replace everything free of charge,the only thing that they reused was the cases,carb,reed block.I never had the cylinder off before that,just was no reason.

Ya, it's crazy a engine company would be so dumb to use such stuff as aluminum.
Almost cost me a nice warbird because of that red crap.
And they are in the USA?

Seems like most you guys like them, the biggest problems is the aluminum screws and that they do not come with mufflers, really don't understand that because they are needed to use them, on the other side great people to deal with and have work done if needed, all my planes are 30cc or less, is the DA 35 a good engine for the money? I know most of you like the bigger stuff but has many of you tried the 35? And what is your opinion of them?

I don't own a DA 35 but reports are very positive. Some even say it may be one of DA's best single cylinder engines with very good handling characteristics and power.

Hmmm, after seeing aluminum bolt failures on other DA engines, any that I've owned were changed to steel bolts. I believe DA released their 60 and 120 with aluminum bolts but later changed them to steel. Someone will correct me if I'm wrong.

With DA, it has been about competition, first and foremost. Aluminum in place of steel to save weight. No mufflers provided, as DA has no idea in what application the engine will be used? Canisters? Tuned pipe? Stock or Pits style muffler? Many, many flights with all my DAs and never had a cylinder bolt failure on any of them. Wound up tight with cans and pipes; hot summer, cold winter. Never a mechanical failure of any kind.
My biggest gripe with DA engines is that they seem to exhibit excessive (to my way preference) over-center rod, pin, crank "play." This is after many gallons of fuel.
By contrast, after more than 20 gallons of gas through my 3W157CSs, they both felt as though they had just come out of the factory. Tight as drums, massive compression, solid as Panzer tanks. Also heavier than comparable DAs. Obviously, sacrifices for weight bring other potential issues.
We are lucky to have so many great engine choices that things like government, politics, human rights, economics, and other intangibles can be part of the decision-making process, yet we can still end up with a high quality product pulling our planes through the sky:cool:

Maybe I can clear up the aluminum bolt deal a little. It is not done for weight reasons. Those bolts shave maybe an ounce off the overall weight. It's done to help stabilize the thermal expansion stresses on the engine. When the engine heats up it obviously expands. With steel bolts the stress on the threaded holes holding the cylinder to the case is higher. Steel bolts will also somewhat limit the expansion process of the cylinder but the rod and piston assembly expands to full potential thus causing an increase in compression that could lead to bad things. When cold the lower rod bearings are a tad loose, this is to allow for heat expansion as well.That's the theory at least. How ip plays out in reality I couldn't say, all my DA engines had aluminum bolts their whole life as well as the two 3W engines I have owned. To the best of my knowledge all DA engines still have aluminum bolts. I have heard of a few cases of them breaking, can't comment to why as I don't have any info. Richard is correct about the muffler. A stock muffler does not fit everything so by purchasing your exhaust separately gives you the option of what suits the airplane best. Again we can go back to the fact most IMAC competitors use DA engines and also use canister exhaust systems. As the saying goes, what counts is when the rubber hits the road so here is a video of my 14 year old worn out DA 150



https://www.youtube.com/watch?v=GQTLS6l28fo

Regardless of brand, a bit of rod / bearing play really doesn't hurt anything unless it gets far worse with time. I'd rather have a bit of working clearance any day then have the fits too tight where parts will fail for sure.

Ok sounds great guys, thanks, the DA 35 is a purchase I will make soon, I do understand the muffler thing I reckon, right now I have set a limit on my plane size and the DA sounds like a winner!

I don't own the 35 either so don't have first hand experience. I have several OS GT33s tho and this engine is the most powerful in the 30 to 40cc class that I Have Played with. Once one learns its idiosyncrasies its an outstanding little mill with really great field manners.

Having said that, you may want to take a look at a thread in Flying Giants someone there compared the DA to the OS. This guys testing seems to favor the DA as more powerful. If true, then the DA has to be a stump puller because the OS already is.

Thanks, I am very excited about this purchase, gas is so new to me but the way the gas come along I am so ready to start flying gas airplanes, you guys all have been. Great help and it is very appreciated! Thank you

If you run the proper gas and the proper oil/gas mixture it really doesn't matter. I haven't had a DLE that I would replace with a DA yet. Have had no problems tuning, running, etc.

That really is what it should be all about. If you are happy with what you have and it meets your expectations then of course there is no need to look any farther. If you are jumping into the gasser game then you may want to more investigating and talking to people who have run multiple brands. Lots of choices out there today, do your homework and buy once as having to buy twice is more expensive then buying top of the line the first time around.

Certainly, with pleasure. The folks in this particular thread are all helpful.

I was I your shoes back in 2009. I had very little experience with gassies having flown a BME 100 twin a few dozen flights back around 98 or so. But when I jumped in 09, it was with both feet, getting rid of most of my glow stuff. Haven't looked back; gas is all I fly. Wait a second, I also fly the electric Vapor with LED lights for night flying. Both my son and grandson learned to fly RC on the Vapor. The best trainer bar none

I prefer engines not coming with a muffler. Why pay for something I may not use. They aren't going to give you the muffler for free.