Johnny C!

After such great success with my Dazzler twin bash,
I am considering getting started on bashing my
Ultra Stik 120 Heavy into a twin using the method
described in this thread.

http://www.rcuniverse.com/forum/m_3590141/tm.htm

It's the same method I used on my Dazzler.

My question is, what size 2 strokes would you gurus
recommend? 4 strokes are sweet, but will cost more
than the 2 strokes. I don't want 3D power, but more
what I would call spirited, like my Dazzler twin.

My main concern for the engines will be power & cost.
A friend suggested TT.90's. I am open to suggestions
about all Mfg's.

Thanks for the help!

Johnny C!

Johnny C!

There seems to be an echo in here...

My friend had suggested the TT or ST .90, but in doing some
research today, I have answered some of my own questions.
The .90's would be way to much power because they have around
2.5 hp.

Another friend used to fly his USH with a Saito .180. Unlimited
vertical. The .180 has 2.8 HP as published, and the .72's as used
in the linked article have 1.2hp. So, I feel that if I can get to
2.5 hp total, I should be about right.

Using the printed HP's for the different engines
as a guide, here is what I find of interest...

OS .46 AX ABL has 1.65 hp for $110 MAP at 13.2 oz
TT Pro .46 BB ABC has 1.43 hp for $88 MAP at 17.1 oz
ST GS-.45 BB ABC has 1.45 hp for $65 MAP at 18.5 oz
TT Pro .46 BB ABC has 1.43 hp for $88 MAP at 17.1 oz

I had decided not to long ago that I would standardize with OS
engines, but with their recent technological advances (i.e. LA's),
I'm not so confident in their new engines. I have had no
experience with ST ot TT engines. Could some give their thoughts
on the engines listed above, i.e. service life, durability & longevity?

Thanks a bunch!

Johnny C!

BillS

If I hade 90’s available I would use them. If 45’s were to be used I would use three of them.

Bill

jrf

My Feedback: (551)

I'm always amazed when an otherwise intelligent (I assume) person starts comparing published hp figures. Come on folks, those are created out of thin air for marketing purposes. If you think a 2 stroke 90 comes anywhere near the usable power of a 180 four stroke, you either haven't seen them both fly, or you weren't paying attention.

The rule of thumb for twin power is to use half the displacement of the single engine. You need to stay with the same engine type, of course. If the USH flies the way you want it to with a 120 two stroke or a 180 four stroke, you should use two 60 two strokes or 90 four strokes.

And please remember that some horses are a lot stronger than other horses.

Jim

Johnny C!

Jim, I know about marketing and sales, so thanks for the compliment.
Thats why I said "published" HP's. It was for comparison only with
the thought that they were all fudged in the same direction. I will take
both posts comments into consideration.

The reason I thought .46's might be OK is because I have an OS .70
on my .46 Dazzler single & it flies great. The linked article uses to Saito
.72's for his USL & he says it flys fine. I will look at the published HP's
for the OS .70 & the Saito .72 for comparison. I will look up what
engines were recommended for the US, also...


What do either of think about the ST &/or the TT's?
I have no experience with either.

Thanks for the input.

Johnny C!

Patto

I have had several SuperTigre engines and I think it's basically a crap-shoot. I have had some that ran forever like champs with a lot of power and great reliability, performance, throttle transition, and slow idle. I have had others that were unpredictable and just a complete headache. My most recent experience was with a G90 that I eventually sent back for replacement. One thing I've found with ST's is that their low-speed mixture is very very sensitive to adjustments, so really only turn 1/8 at a time if you find yourself having to make changes to the idle mixture. For the money, the ST's may be a good bet.

I recently ordered my first twin and decided on two GMS .47's for it. ST's are a little cheaper, but I figured I'd try something new.

jrf

My Feedback: (551)

My experience with ST has not been good. I have had a 2500, a couple of 90s and a 2300, and have attempted to tune several of the smaller STs for other club members. The 90s were serious shakers, the larger ones had to have Perry carbs to run well (there goes you savings) and we could never get any of them to run consistently from one flying session to the next.

My experience with TT is limited to the 46 and a couple of four strokes, but they all seemed to run very well.

I had a USH and flew it with an OS 160 two-stroke and a Moki 1.35. It did not have unlimited vertical with either engine, but it flew well with the 160. The minimum power I would put on the twin would be 75 two strokes. My personal choice, though would be Magnum 91 four-strokes. The Magnum four strokes run very well (and have a good reputation), make reasonable power but less than an OS or Saito, and don't cost an arm and a leg.

http://www.hobbypeople.net/gallery/210970.asp

Given the fact that the linked article used a USLight, I'd say the Magnum 91 four-strokes would fly yours just about the same as the Saito 72s fly his.

Jim

Johnny C!

Jim,
Tower has the ST G-75 listed for $109. Sounds affordable
to me. I really like 4 strokes, but since I'm buying 2 of these,
I would prefer to go the less expensive route & do 2 strokes.

My focus at the moment, subject to change, of course, is the
G-75. When compared to the Moki 2.10 at a published HP of 4.95 HP.
While I never saw it fly, a friend had this combo & from what other friends
have told me, I believe that amount of power is going to be more than
I want. So, 2.18 HP x 2 seems about right to me at this point.

Can you & P-D tell me more about the nature of your problems
with the ST's?

I really appreciate your time & input here.

Thanks!

Johnny C!

BillS

Evaluating engines by horsepower makes me very uneasy.

Bill

Johnny C!

Bill, I agree that it's not perfect, but what other guide do I
have to choose engines for a plane that I have not flown?

Let me pursue this another way.

What engines would you recommend (2 stroke preferably),
for this project & why? Reliability is paramount & then cost...

Jim IM'd me with a very good point. I cannot compromise
on reliabililty of the engines for a twin. His comment was,
if I can't afford really good engines, I am asking for a
guaranteed crash, when one dies at the wrong time.
I will take this to heart.

Thanks again for the input guys!

Johnny C!