Indiomike

My Feedback: (5)

It's okay. I'm just having a bad day.

Although I don't post very often, I check several sites such as this one just about every day on topics that are of interest to me. I constantly see questions from people who ask "What is the best this or that". I truly believe a question like that cannot be answered. The best oil for one person may be the worst oil for someone else. So when you find someone saying brand XXX is the best, you will likely find someone else telling you it's the worst or at least not the best.

What's best for me may not be best for you. The bottom line is it's all personal preference.

MTK

ORIGINAL: WI53072 Paul,my commentsin bold italics

Once again thanks MTK You are welcome

Here is what I have decided.

Break in engine on an 18x8 Xoar prop using 32:1 87 octane gas with no ethanol and the Stihl synthetic Ultra oil mix. Can't go wrong with that

After break in, I may or may not adjust my prop, The engine will have ability to turn more prop after break in....you will leave thrust on the table if you don't increase load a bit......I will further research that on the rather extensive SD assembly thread. I will move the mix to a 40:1 using the same gas and the same oil. Can't go wrong with that

This is loosely what Valley View recommended when I bought the engine. However, now I notice that they are suggesting 30:1 on the same motor they recommended 32:1 on not even a year ago. See how fast things change? is it any wonder these same questions are posed over and over? I wouldn't fret that too much.....There is no practical difference between 30:1 and 32:1 mixtures and the engine doesn't really care. If you did the calculation you would realize how small in amountof oil that difference is (in a tankful of gas).....

WI53072

MTK thanks! Indio, totally get what you are saying and you are right as well, there is no one best this or that. I will let you guys know how this works out. I would like to fly this plane at some point this summer!

Paul

Neuhausr

There are not. There are instructions regarding offset and declination and i can apply that to the firewall but it seems like there should be a more exact or easy way to get the engine lined lined up so that it is centered as it exits the front of the cowl. I am trying to keep from drilling a bunch of holes in the firewall till i get it right. Thanks for the reply.

oldtimer4759

hi, re lining the engine up on the firewall, I have several ESM models, this is what I do, it works for me, I sit the model on its tail, up against the bench, sit the engine in place, fit the cowl over the top, line the engine / spinner up with the cowl, take the cowl off, mark the stand off holes, that is where the engine goes, that way everything lines up, you will obviously have to trim the cowl to clear the engine, as to offset for the thrust line and so on, I havent really noticed much difference when it is flying, if there is I mix trim into it on the radio.
Oldtimer.

Neuhausr

Fantastic information. That is exactly what I need to get this beast finished. I have already made a thrust plate so hopefully the rest will be easy. Thanks again.

Brettis1

I have a new 35 RA. This is my entry into gassers. So whats the method of starting the very first time. Choke with a few turns of the prop  and then back off? what throttle settings ? just off idle?
I dont want backfiring and wrecking props and hubs and things with the first run

Cheers

skillet92

I have two of these and while I won't say to do this to yours, this is what I had to do to mine. Both would not start out of the box till I reset both needles to 1 1/2 turns. On my gassers I always remove the choke plate and solder the hole closed but for some reason neither would draw fuel till I reset the needles. Both. Are great running engines. I have one on a GP Super sportster and the other on a H9 150 mustang. Both turning 20x8 props. The sportster has an APC and the Mustang has an xoar ww2 prop.

Lifer

My Feedback: (1)

Plus 1 on the above. 1.5 turns and solder the hole in the plate to improve choke function.

Brettis1

i'm just about ready to mount it in the test stand and I noticed in the spark plug cap there is a plastic insert and a spring and I cant see any way that the center contact will not come into contact with the plug! maybe there is something missing.I hope to get a photo to explain.can anyone get a quick snap of the inside of theirs.

rcguy59

My Feedback: (8)

Bin the spring and push the plug boot onto the plug until it completely covers the hex flats on the plug. Crisis over.

Brettis1

Ok,  thanks for that. it just seems that there is nothing in the cap  for the plug electrode to come into contact with.will try and see what happens.

Indiomike

My Feedback: (5)

There are two springs within the spark plug cap. The large one which usually sticks partway outside the plug cap is to insure a good ground contact. There is a very small spring all the way back inside the plug cap which will contact the top of the spark plug when fully inserted, meaning that the plug cap will go over the hex portion of the plug. There is a resister positioned so as one end is in contact with the tiny spring and the other end in contact with the main ignition lead. The CM6 spark plug is a non resister type plug since a resister is already in line as described above.

Mike

WI53072

Guys,

I am well on my way with my DLE 35RA everything works very well idle to full throttle no hick-ups and I have several introductory flights on the plane now. However, I have a few follow up questions. I am wondering if it is preferred to remove the spring return on the throttle and allow just the servo to open and then close the throttle? And two, it seems I have no RPM change from half throttle to full throttle. Meaning full power is at half throttle and full throttle? Is this a radio adjustment? or a geometry problem with my servo arm/pushrod or is there a setting/adjustment I need to make on the engine that will broaden my throttle spectrum. I am using a early version Spektrum Dx7 which does not have any throttle curve settings. I just want to make sure that it is not an engine issue I need to address.

Thanks Guys!

Paul

AA5BY

To gain better linearity, there are a couple of options. One is to mechanically configure the linkage and the other is to do a transmitter work around. The mechanical method is harder to do as well as difficult to set the throttle kill switch if one is used.

The transmitter method is done by noting and adding the up & down throw percentages and while maintaining the total sum, changing the values so that the low throttle percentage is about half of what the upper is. The reason it works is that below half stick controls the low percentage and above half stick the high. That means with the low set half the value as the up, the lower half of stick travel controls much less of the servo travel and thereby increases the servo resolution for the lower half, whereby the upper half of the stick controls twice as much servo travel than the low and has less resolution.

The effect is better linearity with more ease to adjust the idle and more ease to jockey the throttle for the correct power when landing.

Indiomike

My Feedback: (5)

W153072

As to the first part of your question I advocate leaving the throttle return spring intact. The spring pressure won't cause any excessive power drain by a decent quality throttle servo. The spring will also return your throttle to idle in the event of a linkage failure.

If you do choose to disconnect it, just unhook it. Don't remove it from the carb. It is needed to help keep the throttle butterfly centered.

Mike

WI53072

Thanks again Indio. I was leaning towards leaving the spring in-place.

Paul

karolh

AA5BY,

This sounds like an excellent idea to try as my radio does not have a throttle curve plotting capability, plus this ought to be much easier than fiddling with the linkage geometry which can be very time consuming.

Is this a straight ATV % reduction on both of the throttle functions or does this also affect the positioning of the servo arm on the output shaft. At present my throttle is at 100% in both directions with some expo added.

MTK

I always disconnect the return spring and move it down to the larger hole closer to the pivot. It effectively reduces spring tension but doesn't eliminate it completely. There still is return to idle action except the tension is 1/3 of what it was stock.

BTW- this little engine starts and runs great. I have about 2 gallons through mine and it still needs more break in but is getting closer. Not in the same league as the OS33 in overall power but its field manners are better.

Throttle linearity for walbro carbs is practically nonexistent. Afterall, most walbro's are designed for two running conditions, idle and full. Unless the carb has been factory modified with a longer arm already, that's where I start, changing the arm to one about 1" long. They are commercially available in aluminum. But I make my own from phenolic stock.

Throttle curves are straight forward in today's computer radios. The curve I use that suits walbro carbs in all the engines I've played with to date starts with an output that's a couple percent greater than input up to around 25% of servo travel. The curve is then flat from about 25% to about 60%. Then the curve becomes vertical to 100% servo travel. It's sort of a reverse "S"....I've found that walbro needs some coaxing just above idle hence the higher movement just above idle, Then it needssmaller increment ofbutterfly opening to about half open. Once half open, walbros are enabling near full power already (probably 80%) so having the servo open the butterfly to full quickly gives you the rest

WI53072

AA5BY,

Thanks for the suggestion. However, due to the geometry of my set up my low end % (idle) is much higher 131% compared to the top end full throttle being set at 60%. So my total range % equates to 191%. So if I am following your suggestion based on my set up, my idle should be twice as high as my full throttle setting?

Paul

NoFlaps

My Feedback: (131)

Can anyone tell me the distance from CL to CL of the muffler bolt-holes on this engine ?
I'm looking to replace my Pterodactyl 35cc rear-port engine that has a custom muffler to fit round my nose retracts...I'd like to use the same muffler if I can.
Thank you,

Sean

aerobear

My Feedback: (4)

Drawing courtesy of dlenginesaustralia.com

rcguy59

My Feedback: (8)

38mm.

Brettis1

In the plastic bag containing the muffler there was a diagram of the screws and washer configuration. Apart form the translation saying they were gaskets the picture shows a doubling of them e.g. one flat washer then one spring washer followed by another flat and spring washer. This seems very odd. Ive never come across this before.

Brettis1