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RE: St 90 break in today - 3/2/2006 11:02:07 PM   
Hobbsy



Posts: 10871
Joined: 12/2/2001
From: Colonial Beach, VA, USA
Status: offline 		Ernie, I've been running my Fox .74 ABC as a Diesel for about 10 years and no issues or changes at all. The ABC engines have a tremendous ability to adjust to however they are run, I probably put about an hour on the .74 as a Glow engine before conversion to Diesel. My La .46 and LA .65 of course are AB? and no issues there either runing as Diesels. My 2 Irvine .40 Diesel are stock ABC engines with the smaller bore and longer stroke of the Q 40 glow engine. This has been raised before but I personally don't think it's a cause for concern. Thanks

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       Post #: 51

RE: St 90 break in today - 3/3/2006 3:10:27 AM   
Gizmo-RCU


 

Posts: 988
Joined: 9/17/2002
From: Athol, ID, USA
Status: offline 		Ernie,
I will try and fly as soon as the weather gets a little better. I will tach and fly to see what develops. The engine is way over-size for a UCD 46 so it may be a little difficult to determine true improvement as there is so much power available, but I will try. I will also see how midrange and lower end compare.

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       Post #: 52

RE: St 90 break in today - 3/3/2006 3:04:04 PM   
Cyclic Hardover



Posts: 7238
Joined: 5/7/2002
From: New Mexico, USA
Status: offline
quote:

ORIGINAL: Gizmo-RCU

Ernie,
I will try and fly as soon as the weather gets a little better. I will tach and fly to see what develops. The engine is way over-size for a UCD 46 so it may be a little difficult to determine true improvement as there is so much power available, but I will try. I will also see how midrange and lower end compare.



It shows your around 2500 ft altitude. Your numbers can be around a 6% loss in power or rpms compared to those guys at lower level-FYI. I am here in Albuquerque (5000ft) and this difference is very noticable.

< Message edited by Cyclic Hardover -- 3/3/2006 3:10:29 PM >

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       Post #: 53

RE: St 90 break in today - 3/4/2006 12:58:24 AM   
Gizmo-RCU


 

Posts: 988
Joined: 9/17/2002
From: Athol, ID, USA
Status: offline 		The field is almost exactly 2500ft. per my GPS. It never really presents any problems except perhaps with the most underpowered planes and I don't have any of those. I run 5% in my MVVS engines and they thrive. Everything else gets 15% all with Castor /Syn, no problems thus far.

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       Post #: 54

RE: St 90 break in today - 3/4/2006 12:51:05 PM   
Cyclic Hardover



Posts: 7238
Joined: 5/7/2002
From: New Mexico, USA
Status: offline 		My extensive testing on this was calling up somebody and saying "hey, what are you getting on this setup?" Crude but reliable since they had the exact same setups. Take my Jett 90 on the UltraSport. Dub gets 14,000 rpms down in Texas and I am about 12,500rpms here with the same prop and thats the best I get. Its still a mover but does lack in performance.

My DC F-20 with a Jett 50. I get about 115-120mph here and guys on the coast are pushing 135-140mph. Altitude does play a big part on it. I just wanted to tell you this so that when your numbers are lower than others, its not the engines fault. A few years back, my "ballpark" theory was about a 3% loss in power/rpms for every 1000ft altitude and it seems to be close on every setup I have compared to others.


< Message edited by Cyclic Hardover -- 3/4/2006 12:55:39 PM >

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       Post #: 55

RE: St 90 break in today - 3/6/2006 12:48:53 AM   
Ernie Misner


 

Posts: 3162
Joined: 7/5/2002
From: Tacoma, WA, USA
Status: offline 		Took a peek at mounting my G90 on the Ultra Stick 60. With the stock mount turned horizontally, the mac's header and mousse can will still come out down below, just inside of one landing gear leg. The spray bar is in good position with the tank this way. I will move the engine back as far as possible. I can get it nearly back to the firewall if I put 90 degree bends in the alum tubing that will exit the tank. I still will probably have to mount the servos back. The playing with different can sizes and header lengths will be fun.

Ernie

(in reply to Cyclic Hardover)
       Post #: 56

RE: St 90 break in today - 3/6/2006 1:22:07 AM   
Cyclic Hardover



Posts: 7238
Joined: 5/7/2002
From: New Mexico, USA
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quote:

ORIGINAL: Ernie Misner

Took a peek at mounting my G90 on the Ultra Stick 60. With the stock mount turned horizontally, the mac's header and mousse can will still come out down below, just inside of one landing gear leg. The spray bar is in good position with the tank this way. I will move the engine back as far as possible. I can get it nearly back to the firewall if I put 90 degree bends in the alum tubing that will exit the tank. I still will probably have to mount the servos back. The playing with different can sizes and header lengths will be fun.

Ernie


I want to bring up something that happened a couple years back on my G90. Make sure your fuel line to the carb does not have any 90 degree angle on it out of the firewall. It won't look pinched but it might be. Ground runs will be fine but will get lean and overheat in the air. It took a month for me to find this.


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       Post #: 57

RE: St 90 break in today - 3/6/2006 2:40:37 AM   
Gizmo-RCU


 

Posts: 988
Joined: 9/17/2002
From: Athol, ID, USA
Status: offline 		Ernie,
Quit sending over your crappy weather, flew once today and it was cold. Trimmed out a trainer for a fellow who promptly crashed it. He told me he was a "little rusty" had actually flow scale Mustangs, last time several months ago.
He did not have a buddy box so I asked him If he wanted me to hand him the box or wait for a buddy box. I had the plane trimmed hands-off low power and gave him the box. He went inverted and promptly crashed it nose first upside down. He claimed the engine quit and he had never deadsticked before....so much for experiance.
Poor guy, he wanted to fly so bad he didn't give me the straight stuff.......
Will change carbs weather permitting.

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       Post #: 58

RE: St 90 break in today - 3/6/2006 4:47:40 AM   
Mike Baldwin


 

Posts: 179
Joined: 1/17/2006
From: Gilbert , MN, USA
Status: offline 		I have a ST 90 coming from Tower this week. I am glad to here so many good things on this motor. I read the reviews on the moter before I ordered it, and they were mostly good. I was mainly just looking at the price. As per the origonal post, is that what ST recomends as a breakin procedure. Just wondering how you come up with the run times and rpms. I putting it on a Tiger 60.

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       Post #: 59

RE: St 90 break in today - 3/6/2006 5:01:15 AM   
Cyclic Hardover



Posts: 7238
Joined: 5/7/2002
From: New Mexico, USA
Status: offline 		You may want to just re-read the whole thread and decide for yourself. You'll have yourself a very good engine that will perform well on your Tiger 60. If it were me,I would put a 12/8 prop on it to start with and see how it goes for a while. However, my opinion of a break in is not shared by many here. Good Luck

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RE: St 90 break in today - 3/6/2006 7:20:36 AM   
Ernie Misner


 

Posts: 3162
Joined: 7/5/2002
From: Tacoma, WA, USA
Status: offline 		Ed, I'm thinking of putting the 90 degree bend right in the aluminum or brass tubing that exits the tank at the firewall, not in the silicone tubing. Hopefully your tip will help someone ward off that problem.

Mike, you should have plenty of power on your Tiger 60 as I will with my US 60. Let's keep in touch and see how it goes. Hopefully you won't have balance problems like with the US 60.

Ernie

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       Post #: 61

RE: St 90 break in today - 3/6/2006 2:17:51 PM   
Mike Baldwin


 

Posts: 179
Joined: 1/17/2006
From: Gilbert , MN, USA
Status: offline 		I know what you mean about the nose wait. I was going to put a FX 61 on the plane and I would have had to add a whole lot of lead up front after already putting the battery and every thing else as far forward as possible. I dont have a small enough scale but I figure that it was about 5 or 6 oz. I think that the ST is about that much more in weight. I hope.

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       Post #: 62

RE: St 90 break in today - 3/6/2006 8:15:28 PM   
Ernie Misner


 

Posts: 3162
Joined: 7/5/2002
From: Tacoma, WA, USA
Status: offline 		Mike, apparently the Tiger is just the opposite of the Ultra Stick, which needs weight in the rear! Trade you engines?

Ernie

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       Post #: 63

RE: St 90 break in today - 3/6/2006 11:44:22 PM   
Mike Baldwin


 

Posts: 179
Joined: 1/17/2006
From: Gilbert , MN, USA
Status: offline 		My Tiger has a heavy tail. Seems to be a common thing on the Tiger. My 90 should be here Friday. Can't wait, this will be my biggest 2 stroke engine. I have a 16 oz tank in the plane, will this be big enough. I run 10 % in all my other two stokes, will this be all right. I have been runing 12 oz tanks in my 60's and get between 13- 15 minute flights.

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       Post #: 64

RE: St 90 break in today - 3/7/2006 6:10:40 AM   
Gizmo-RCU


 

Posts: 988
Joined: 9/17/2002
From: Athol, ID, USA
Status: offline 		16oz. is a lot of tank should give you 15 to 20 mins. of sane flying? I use a 10 oz and that is more than enough for me and then some.

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       Post #: 65

RE: St 90 break in today - 3/10/2006 3:20:37 AM   
Mike Baldwin


 

Posts: 179
Joined: 1/17/2006
From: Gilbert , MN, USA
Status: offline 		I got my G 90 today. I ran two tanks through it using the procedure in the book that came with it. At the end it was idling pretty good, had a little hesitation from low to high, but not bad. Lots more power than my 61 FX. The Tiger is going to scream. I would have some tach reading for you but that order has not arrived yet. I did multiple orders from Tower to cash in on more savings. All in all I saved 80.00 dollars on a little over 500.00 in goodies. Of course saved is a relative term, I just added 80.00 more in stuff. Anyway when I get my tach I will post some readings.

(in reply to Gizmo-RCU)