I'm new to the four stoke deal, and this hobby itself. I'm looking at the Magnum XL 91FS AR the Saito FA-91 S, and the O.S. FS-91 II Surpass. I see that the O.S. has a high rpm of 12000, and the saito of 11500, and the magnum 11000. Is this going to make a difference in performance; as far as hovering and being able to climb out of it with no problem? Also further down the road would I wish that I had the extra 1000 rpm?
Which engine to pick? I'm on somewhat of a limited budget; but I'd rather buy quality and only buy once!


thanks for the help!@

All the engines you list will work fine on the plane. See the other threads on this plane for much additional infromation. OS and Saito both have parts readily available. Not sure about the Magnum as there if only one flying locally. Seems to run fine. High end RPM doesn't really tell you anything since the test would need to be made with the same prop and fuel in the same conditions. Good luck.

EXCAP232

If you're on a budget get a Magnum xls .91 two stroke for $150.

If all else is equal 1,000 rpm is a huge difference but the companies numbers are meaningless.

Who has the best price for the magnum. Where can I fond it?

If you're going with Saito then I would get the 100 instead of the 91. The Saito 100 will make more power than all the engines you listed. I don't know if the price is still the same, but I gave $265 shipped for my Saito 100 from Chief Aircraft.

Wade

Quantum and Hobby People both sell the Magnum for ($150) but Quantum has free shipping. You just missed the sale at Hobby People, only $120, sorry.

I have this engine on my UCD and trust me, it's plenty. Comparable to the Saito 100.

The only complaint I have is the muffler back keeps vibrating loose.

You have the magnum 2 stroke. I was talking about the four stroke. the four stroke is only $20 more. wouldn't it be better to go that way

I have a Magnum XLS-91A 2 stroke on mine and I love it. It will hover at a little over 1/4 throttle. I used lock tite on my muffler to keep it from rotating. It fixed the problem. Otherwise it is a great engine for the price. I am running an APC 15-4w on mine. I don't have RPM numbers though. A 14-6 is good as well.

You can't trust advice from someone named Finnz from Wisconsin. Just kidding of course! Mike, you remember me, you bought the BME 50 from me? Are you still running it?

Wade

No, I sold it with the Edge last Fall. I got a 1/4 scale Decathlon with a ZDZ 40. The BME was great though. I ran about 5 gallons through it and it never have me a problem. How are things with you.

Mike,
Doing fine. How do you like the ZDZ compared to the BME? Which one do you think is the smoothest running? I've heard the ZDZ 40's are powerful engines.

Wade

I like it allot. It is a little smoother than the BME. I only have 5 flights on it. This is the ZDZ 40 Sportsman with reed valves. It doesn't have the power of the Rotory Valve. It flies a 20lb Super Decathlon very scale. I will definitely get another. Maybe the 50.

Dlmob,
Something to keep in mind is the weight. The Saito 100 is very light at 20 ounces. I don't know what the Magnum 4-strokes weigh. I think you'll find the OS 4-strokes are a little heavier than the Saitos. I've heard the Thunder Tiger 4-strokes are really powerful, but I think they are pretty heavy.

Mike,
From what I've been hearing the DA 50 is a real winner. I haven't seen one run but I've seen videos of it, seems to be a stump puller.

Wade

I am trying to resist getting any more big planes. I have the Decathlon, and a 1/4 H9 Cap with a Fox 2.4, the UCD, a Lanier Citabria, and just sold my Ultra Stick 60. I want that new H9 Funtana. Should be out the end of the month. Have you been on my web site lately. Check it out.

www.ros********.com

Dlmob,
I found some engine weights for you:

Magnum XL-91RFS/22.4 ounces. Got this weight from Hobby People's site.

Thunder Tiger F-91S/26.2 ounces. Got this weight from AceHobby's site.

No doubt that the Saito 100 is the lightest. There is no weight savings with the Saito 91, may as well get the 100. The Magnum weight isn't bad if that weight includes the muffler. I think the OS 91 will weigh about the same as the Magnum. The TT is too heavy. No doubt that the Magnum is quite a bit cheaper than the Saitos. Hope this info helps you out a little if you haven't already made up your mind.


Wade

Mike,
I see you've been working on your site, looks great! I think this plane will be a good flier, due out in June:


http://www.extremeflightrc.com/product_html/60Edge.htm

I've in line for one when they get them, will use my Saito 100 on it.



Wade

That is nice. I really like there Yak. A DA 50 would be perfect for it.

Yep, it sure would.

so with being on a budget . would it be a 90 2stroke or save for a little bit and get a 100 4 stroke. Also keeping in mind I'll be using the engine for later models as I progress down the line. :stupid:

For the money you can't beat the Magnum 2 stroke .91 for $150. I am running a 15x4W APC on mine and with about a gallon through it , it peaks at 10,900 on 10% fuel with the stock muffler/no baffle.

The first tank peaked at 9,700 and it keeps getting better.

The Saito 100 won't beat those numbers but some people just love the 4-strokes. I prefer the 2 strokes, both will do the job.

If you go the 4 stroke route, get the 100 not a .91

geoHarry,
I am going to have to disagree with you. I was turning an APC 16x4W at 10,300 on my Saito 100.

I was getting the same RPM's with a Zinger 16x5, with quicker spool up than the APC(the Spool up is negligible w the APC, but noticably less with the Zinger).

But of course you do pay for the extra power and 4-stroke sound.

Gotta love the putta-putta.

I really can't compare your numbers to mine.

16x4w 10,300 yours

15x4W 10,900 mine

fuel?


hard to compare but they look similar to me

Well I guess the problem is that you wouldn't want to put a 15x4w on a Saito 100, cause it would over-rev. I am just saying I don't think the RPM's/Throttle response would be the same on a Magnum 91 2-stroke running a 16x4w.

2-stroke versus 4-stroke, they both have their advantages and disadvantages. 2-strokes are simpler in design and cheaper to buy. 4-strokes characteristically have more torque, especially at lower rpms, swing a bigger prop more easily, have that cool sound, and seem to be more fuel efficient. Both have great throttle response if adjusted and propped properly, but the 4-strokes seem to have an edge here. The Saito 100 is very light, and I think any .91 size 2-stroke will be about the same weight so this isn't an issue. One drawback to the 4-stroke is you may occasionally have to adjust the valves, but it only takes a few minutes to do. I personally would rather have a Saito 100 on the UCD3D if I could afford it. If you look at all the posts here this engine is definitely the most popular choice for this plane. Dozens and dozens of people can't be wrong. If you want to do a lot of hovering around then I think the 4-stroke is the best choice. I think 2-strokes are great engines as are the 4-strokes, but the Saito 100 would be hard to beat on the UCD. The Saito 100 is a very popular engine, so the resale value would probably be very good if you ever wanted to sell it. The Saito has a 3 year warranty, pretty nice since it's longer than most. This is my opinion, and I'm sticking to it! Sorry for the rambling on.

Wade