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Old Jan 28, 2013, 12:09 PM
Fueled by Arabica Beans
ChillPhatCat's Avatar
United States, NY, Syracuse
Joined Oct 2008
4,037 Posts
Quote:
Originally Posted by kerwin50 View Post
a higher pitch will give you the speed you need. you may need to drop in prop size to get the rpms up.
A G62 on a pipe flys an AT 6 texan well over 150 mph.
Yup, this is about all that needs to be said actually. I'm sure that it's only a prop away from 120+ with a DLE 55.
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Old Jan 28, 2013, 10:39 PM
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Nav_Aids's Avatar
Canada, MB, Winnipeg
Joined Nov 2011
332 Posts
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Originally Posted by kenh3497 View Post
I have a fairly high performance motorcycle that many have said need to run 92 octane fuel for maximum performance. I decided to do a test of sorts. I checked mileage with my normal 87 octane fuel and 92 octane fuel.
Ken your kind of comparing apples and oranges here (max performance and max fuel mileage), your bike will probaly get better performance at full throttle runs because the computer will go to max performance settings. On most automobiles today the computer constantly tries to put more ignition timing into the engine but there is a knock sensor that the computer constantly checks to see if it is over timing the engine. Most motorcycles don't use a knock sensor so timing is set to a conservitive setting.


Quote:
Originally Posted by kenh3497 View Post
IMO the 92 had a delayed burn which equates to less cylinder pressure / less performance. Which required a larger throttle opening to make the same power. My "butt dyno" or seat of the pants could not detect a difference in performance.
I agree, from my own personal experience and testing in non-computer engines and not adjusting the timing.


Quote:
Originally Posted by kenh3497 View Post
Is / was this a valid test? I don't know. I do know it cost a lot more money to fill the tank on my bike using the 92 octane fuel with little if any gain. If I had been able to advance the timing of the engine I may have seen a tangible gain.

Take the above for what it's worth.
It is a valid test if one is comparing fuel mileage.

Quote:
Originally Posted by kenh3497 View Post
I don't believe our small engines warrant using anything but 87 or 89 octane fuel. Using the same FRESH fuel from the same supplier every time would be a better bet IMO.

Ken
Without getting real technical, it all boils down to, the smaller the displacement the less sensitive an engine is to unstable combustion. Oh and if you want to get better gas mileage just put some nitro in the 89 fuel. With the extra cylinder pressure you'll use less throttle. Mind you, with the price of this fuel your gas mileage will be expensive.

Ray
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Old Jan 29, 2013, 04:21 PM
The Prez....... again
kenh3497's Avatar
United States, IA, Rockwell
Joined Jul 2011
4,151 Posts
Quote:
Originally Posted by Nav_Aids View Post
Ken your kind of comparing apples and oranges here (max performance and max fuel mileage), your bike will probaly get better performance at full throttle runs because the computer will go to max performance settings.

Ray
The computer is in my right wrist. This 2002 "old girl" has four carbs feeding four thirsty cylinders.

Ken
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Old Jan 30, 2013, 08:54 AM
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epoxyearl's Avatar
United States, MD, Elkton
Joined Oct 2011
8,951 Posts
As an old racer,going to 92 octane rated gas is only an advantage if you increase the ignition advance to a higher setting.

I'm lucky enough to be able to purchase unleaded Avgas (100LL)...With a low pitch prop,I could comfortably use 38 Degrees advance. But if I went to a 14" pitch, pre-ignition required some retarding of the advance.

We discovered (Duh) that you can only go so fast with a given engine...

In your quest for speed ,have you considered a JetCat Turbo-prop?-That revolver should become an automatic weapon, then.
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Old Jun 16, 2013, 11:41 PM
flyboydale54
Near Watertown, NY
Joined Sep 2005
9 Posts
Forgot the Quote, so basically redid this post with Quote and since it would not allow me to delete it entirely, added a few words of explaination.
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Last edited by flyboydale54; Jun 17, 2013 at 12:33 AM. Reason: Forgot the Quote, so basically redid the post with Quote:
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Old Jun 17, 2013, 12:22 AM
flyboydale54
Near Watertown, NY
Joined Sep 2005
9 Posts
Quote:
Originally Posted by S3NFO View Post
A common misconception that higher octane gives you more power. Octane is an ignition inhibitor that makes it harder to light gasoline on fire which is added to gasoline used in higher compression engines to prevent detonation (pre-ignition). Higher octane gas only helps if you have a higher compression engine (in the 13:1 range), so on a DLE-55, 92 octane is a waste unless the compression has been increased.
While I am new to gassers, I recently bought a 50cc gasser plane with a DA50r already to fly from a friend in the club that only flew it a few times. At the pumps now we can buy 91 Octane without Ethenol Alcohol in it. I immediately made the change after I put a gallon of gas through it that was the same as my friend used of the ethenol type, and noticed a power increase. Since it is still being broken-in still, I have to stick with the normal recommended Penzoil 2-cycle oil until it is broken in to properly seat the ring. After calling the support at Desert Aircraft, they told me that I can switch to synthetic oil after putting 4 gallons through it. I had a quart of 100:1 Synthetic Amsoil I was going to use, but since the 100:1 ratio concerned me on possibly a lack of lubrication, I inquired to the factory support team of its use. They advised me that there is more carbon buildup than they would like to see when they tear them down. They advised me to use Red-line 2-cycle Racing Oil and to mix it 40:1! This will avoid the excessive carbon buildup from using the Amsoil they said. I will have to order this oil since nobody sells it locally according to the dealer search I did from their web site. Since carbon buildup will cause detonation, I will stick with the factory support recommendations. From my reading on the Red-line web site, this oil has special formulations that keep this carbon from building up on the internal parts of the engines.
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Old Jun 17, 2013, 12:31 AM
flyboydale54
Near Watertown, NY
Joined Sep 2005
9 Posts
Quote:
Originally Posted by ahicks View Post
Regarding the original post, we're talking about somebody new to gas - and suggesting he start right into custom blended fuels and modified compression ratios?

Maybe I'm just getting old, but I think the DLE 55 plan is an excellent one with plenty of (factory) support nearby if (when?) needed. Start there, and when he gets his knees to stop knocking as it comes right out of the box, then see about doing something to make it go faster.... Walk before running?
Nobody is suggesting you start right in custom blending your own fuels. While I understand your possible frustrations with all these posts, I personally enjoy reading them because they fill in the voids of my lack of knowledge I am seeking. If you do not read these articles and strive to look up words you do not understand, you will never reach the level that these higher level gentlemen are expressing in this forum. Every little detail in these posts should be serving to enlighten you on the many changes one can make to achieve the performance level one is seeking. For you and your knocking knees, just by unpacking your new model, think about us guys that push the speed envelope to over 150mph and perhaps 200mph. My knees will be knocking when I achieve this level of speed. Just changing from a Super Tigre 75 in my Bridi Super Kaos 60 to a Super Tigre 90 Engine made my knees knock, but then again, I love the part where the nose wheel lifts off the ground in a few feet and I can pull it vertical and climb right up out sight. Now for protecting my knees, I can wrap some carpet foam around them and use a couple of #44 Rubber Bands for now until I get used to the increased speed and vertical performance. Now to continue reading in these forums about these DLE-55's and perhaps about my DA50r, I may just be able to boost my performance and RPM's to where I need them to be to achieve that in these three 50cc gassers I just bought, which seem to need a little more performance from the engine to achieve the speed and unlimited vertical I need to be able to safely do some occassional 3D flying, yeah that is what I am talking about. Enjoy your transition from electric to gas, it is a learning curve of which I am caught right in the middle of, now that I have purchased three gassers to add to my collection of fine adult toys, :-).
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Old Jun 17, 2013, 12:40 AM
flyboydale54
Near Watertown, NY
Joined Sep 2005
9 Posts
Quote:
Originally Posted by epoxyearl View Post
As an old racer,going to 92 octane rated gas is only an advantage if you increase the ignition advance to a higher setting.

I'm lucky enough to be able to purchase unleaded Avgas (100LL)...With a low pitch prop,I could comfortably use 38 Degrees advance. But if I went to a 14" pitch, pre-ignition required some retarding of the advance.

We discovered (Duh) that you can only go so fast with a given engine...

In your quest for speed ,have you considered a JetCat Turbo-prop?-That revolver should become an automatic weapon, then.
I tried that turbo-prop change in the Real Flight Simulator. Man I love this modification, but it did require some substantial CG adjustments using trial and error. I also had to lengthen the landing gear to allow for the larger prop. This is real fun to fly. In real life, it would be fun too if I could afford the Turbo-Prop engine, and stand the stink of Jet Fuel, LOL. Larger engines often require making a new set of landing gears to get the ground clearance.
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Last edited by flyboydale54; Jun 17, 2013 at 12:43 AM. Reason: Added a sentance about landing gear.
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Old Jun 17, 2013, 01:33 AM
YAY the tourists are GONE
United States, MA, Sandwich
Joined Feb 2010
192 Posts
The most important part with speed is drag. As speed goes up drag goes up exponentially.

Having more power not has not as important as has having a very low drag plane
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Old Jun 17, 2013, 10:00 AM
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gkamysz's Avatar
Chicagoland
Joined Feb 2000
7,392 Posts
Quote:
Originally Posted by flyboydale54 View Post
At the pumps now we can buy 91 Octane without Ethenol Alcohol in it. I immediately made the change after I put a gallon of gas through it that was the same as my friend used of the ethenol type, and noticed a power increase.
Did you retune the needles? If you changed from E10 to straight gas, the engine was leaner on the new fuel.

Greg
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Old Jun 17, 2013, 01:34 PM
The Prez....... again
kenh3497's Avatar
United States, IA, Rockwell
Joined Jul 2011
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Stihl Ultra oil IMO will perform equal to the Red Line oil. The Stihl oil should be readily available locally.

Ken
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Old Jun 17, 2013, 03:25 PM
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bret191's Avatar
Arizona
Joined Sep 2010
17 Posts
Great start!

This is a nice air frame for a sport flying and starting to learn 3D, it flys well but isn't designed for all out speed. The type of foil and amount of drag this air frame delivers is your biggest item when searching for speed. If you want speed out of this aircraft with this engine look at drag. This plane will get to a point where it will take a boat load of money to go just a few MPH more.
If your in hear asking about speed tells me your not a engine builder or wizard so stay away from getting talked into shaving cylinders, porting and doing away with head gaskets ect. For one thing a pro engine tech. is where you want your engine built and not the internet! Besides all that will only gain you a few MPH! You will get MORE by paying attention to all of the basics and mastering these first!
Your on the way to a great set up, as for fuel and oil sense it been mentioned is not where your guna find speed but you will find constant runs and long engine life or problems. Start with a good name brand of gas, 89,92 or what ever you want to spend BUT use the same stuff every run. Oil all most any name brand oil is safe, don't fall for any of these 100/1, 400/1 mixes, stick to the proven, tested mixes! Synthetic is less of a mess and castor is more of a mess, regular motor oil and is between the two. Pick one you feel safe with and use a safe ratio and then tune the engine to that fuel.
Money wise, get a proven pipe and then try different props until you get one you like, smaller props tend to generate mare speed but less torq. and bigger props perform the opposite.
You have a COOL air craft and a nice mill, fine tuned and this bird will amaze you and your buddies!
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Old Mar 24, 2014, 02:16 PM
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kremecheze's Avatar
United States, NM, Albuquerque
Joined Jun 2007
1,172 Posts
i dont intend to jump right into custom modded fuel setups etc...but i can assure my knees will not be knocking, i have been flying for over ten years and mostly jets, so unless its going 200mph, i think i'll be fine. i decided on the dle 55, just gonna mess with prop setups to get the desired results. i am also looking into an evo 15 or dle 20 for my sundowner 50...should be a fun building season
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