ORIGINAL: NM2K
ORIGINAL: madman75
ORIGINAL: NM2K
ORIGINAL: DarZeelon
ORIGINAL: Live Wire
Look at the muffler.
It appears to be the same muffler for all.
That's not the difference.
HobbyKing offers the [link=http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8987]ASP 1.08[/link] for $78.90 and the [link=http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8988]ASP .61[/link] for $61.60...
Those offers for the ASP .91 at $103.85, or at $130.77, do seem quite expensive.
As Dar suggests, I bought the ASP 1.08 (2) when they were on sale at Hobby King. Mine were $70 each.
Ed Cregger
I looked at the 1.08 from HK and thought about it. The shipping comes out to about $35 so the price is higher than Hobbypartz. Hobbypartz is out of the 1.08. I found a place that lists the specs for the .91 and 1.08. There isn't much difference in stated HP. The .91 will fit the fuse opening better than the 1.08. I'll have to grind out about 5mm for the 1.08 to fit. I'm leaning towards the .91 since I now know the difference, I need to decide if I want the remote needle or not. Not sure if there is any running/performance difference between the needle locations. I just have to figure if I want the .91A or the .91AII since the only difference is the needle valve location. Maybe I should go with the remote needle due to missing part of a finger from a prop. LOL
As cheap as some engines are now days, if it's something other than bearings, they become throw away items. If parts are needed, it looks like Just Engines has parts but they are in England.
Here's a link to a review for the .91.
http://www.justengines.unseen.org/ac...Dorling__.html
Thanks all. I didn't know the difference was the needle valve assembly.
Without taking true running engine power measurements and, instead, just reasoning things out, which occasionally works, the larger 1.08 (physically larger, if you are right) actually offers a few theoretical advantages over the more modern .91 engine. The modern .91 is most likely a punched out .61, meaning that the gas ducts in the engine's crankcase would have to be smaller than those of the .61, because of a larger cylinder bore. This would tend to force the designer to focus more on torque production at lower rpm since the gigantic air passageways that are necessary to create a revving engine just aren't there. Remember, I said that this type of brainstorming works out occasionally and not all of the time. Also, an engine with more mass tends to last longer due to less flexing being permitted by the extra metal. Yes, the location of the extra metal is important too, but it just so happens that where the extra metal is removed in such engines is exactly at the wrong places. Remember, we're brainstorming here.
I do have a modern Magnum .91 in addition to the two ASP 1.08 engines. Running/flying them on my Global 90 size Delta wing fighter ARF should demonstrate any difference in power, if it truly exists.
Ed Cregger
Ed,
You seem to be somewhat of an expert on these matters. Which is the way to go? The .91 or the 1.08? It seems the Magnum is pretty much the same as the ASP. Am I right on this? Why is the .91 rated to 17,000 rpms and the review stated that 13,800 rpms was achevied? I have seen conflicting info. on the rpm numbers for the 1.08. I have seen up to 10,000 at one place and up to 17,000 another. What's your take on this and what have you seen from the 1.08's you have? I have seen info. where OS did the same thing with their .91 engines. Basically "punching out" a .61. It seemed to work for OS for a while. I'm just trying to find out the best route to go. So, whats your take on the Magnum .91 as compared to the ASP 1.08 considering the 1.08 is 5mm wider and 100 grams heavier?
Oh, I did some more checking on the shipping. There is a cheaper shipping available for $21 that is for 6 to 21 days delivery. That would put the HK 1.08 at $99.