A/A 21 Super Long Stroke Tests

[Al Hobbs]

Over the past weekend a JAE 21 running a stock A/A 21 SLS engine with stock pipe and header, H-7 prop, and 55% nitro fuel ran 70 mph in Alabama. The only change was to tighten up the head space. Previously, a stock A/A 21 ran 55 mph in a mono, using an Octura X440 prop.

The A/A 21 SLS engines, pipes and lots of parts are in stock.

I hope to have one of the new A/A 45 engines on hand soon for inspection and pictures.

 

[Nigtmare]

What is the price on them?

 

[camaroboy383]

prices on .21 engines, pipes and headers please,,flywheels included with engine purchase or seperate?

alden

 

[NAMBA860]

Over the past weekend a JAE 21 running a stock A/A 21 SLS engine with stock pipe and header, H-7 prop, and 55% nitro fuel ran 70 mph in Alabama. The only change was to tighten up the head space. Previously, a stock A/A 21 ran 55 mph in a mono, using an Octura X440 prop.

The A/A 21 SLS engines, pipes and lots of parts are in stock.

I hope to have one of the new A/A 45 engines on hand soon for inspection and pictures.

AL WHAT MONO HULL WAS THAT in? shane

 

[Al Hobbs]

The mono was a Speedmaster using an X440 3 blade prop.

Engine is $415.00. Pipe with pressure tap installed is $65.00. Header is $25.00. Pipe and header combo is $85.00.

They are available through Steve Winks in Australia, Andrea Cavalli in Italy, Grahame Morgan in England, Jerry at Seaducer Boats, and Troy Davis in California. Of course you can contact me, but be patient as I travel on business frequently.

 

[Al Hobbs]

Sorry, but I forgot to answer one of the questions. The engine comes with a flywheel and carb. You need a needle, either in line or 3rd channel and a cable nut, 1/4 by 28.

 

[WIDEBOY]

I have them in stock check out my web page for more pictures.

www.wideboyracing.com

Thanks

Steve Winks

 

[Archie Stanton]

does the AA SLS version have the Tungsten Counterweighted SG crank like the Cobra?

I'm curious.....I have a feeling these could be some really solid motors.

any thoughts on the RPM vs Torque profile?

 

[Duck899]

does the AA SLS version have the Tungsten Counterweighted SG crank like the Cobra?

I'm curious.....I have a feeling these could be some really solid motors.

any thoughts on the RPM vs Torque profile?

For more pics, go to my gallery... A/A 21

 

[Archie Stanton]

does the AA SLS version have the Tungsten Counterweighted SG crank like the Cobra?

I'm curious.....I have a feeling these could be some really solid motors.

I've had my ear to the ground but I havn't seen any graphs on the Cobra yet and I dont know how it's timed.

For more pics, go to my gallery...   A/A 21

sweet......it looks like copper slugs in the pic, But I'm pretty sure it's heavy metal like it's brother.

looks like the Rat Pack is into some well-designed motors

I'm curious to know what kind of rod-length ratio this thing has;Did Rossi do a good job of setting up the head button like Novarossi did so that it can be tweaked easily for higher nitro configurations?

any thoughts on the RPM vs Torque profile? I've heard the exhaust timing is kinda conservative but if the transfers arent too high, maybe it can be shimmed?

I think the NR Toro Nero peaks it torque around 33K....I'm wondering where this one peaks.

 

[Al Hobbs]

While the A/A 21 SLS design started with the AxeRossi Cobra, there are very few common parts.

We basically kept the same bearings, wrist pin, wrist pin clips and connecting rod. The case is so similar as to be a clone.

Everything else is different. Either in design and/or metallurgy. The A/A 21 SLS is not an AxeRossi Cobra with a different name. It is a different engine.

Next and very important is that this engine was designed to be user friendly. A beginner can get it running well. It was tested on many different fuels, from 30% nitro to 70% nitro content. It runs well basically stock, but if you want to tweak the engine to get more, be my guest.

All I will do to my A/A 21 SLS is to drop the headspace to 0.006". I do not intend to sell an engine that must be sent to an after market guru to get acceptible performance.

However, I am certain that there are people that can tweak this engine to get a bit more out of them. There are always good engine people that can get a bit more out of any engine.

Al Hobbs

 

[Archie Stanton]

While the A/A 21 SLS design started with the AxeRossi Cobra, there are very few common parts.

We basically kept the same bearings, wrist pin, wrist pin clips and connecting rod. The case is so similar as to be a clone.

Everything else is different. Either in design and/or metallurgy. The A/A 21 SLS is not an AxeRossi Cobra with a different name. It is a different engine.

Next and very important is that this engine was designed to be user friendly. A beginner can get it running well. It was tested on many different fuels, from 30% nitro to 70% nitro content. It runs well basically stock, but if you want to tweak the engine to get more, be my guest.

All I will do to my A/A 21 SLS is to drop the headspace to 0.006". I do not intend to sell an engine that must be sent to an after market guru to get acceptible performance.

However, I am certain that there are people that can tweak this engine to get a bit more out of them. There are always good engine people that can get a bit more out of any engine.

Al Hobbs

Do you have any info on the timing numbers? exhaust, transfers, intake open and close?

Can you elaborate on the differences in the piston and the head button? If you know the're different, then certainly you would share them

 

[Al Hobbs]

Exhaust is just under 180 degrees. Intake is just under 125 degrees. The problem with putting exact numbers out is that someone will say those number are no good, or that another brand's numbers are better. If I were to say that the exhaust was exactly 180 degrees, someone will measure their engine differently and make a big deal out of it, whether they can measure correctly or not.

Different numbers do not necessarily mean better or worse performance. You might like one brand in a mono and another brand in a rigger. Your experience is the most important measure of what kind of performance you will get out of any engine.

The head button chamber is a different shape and volume than the Cobra head button.

Rossi makes their pistons individually for each sleeve. They do not just make a batch of pistons and a batch of sleeves. A different sleeve shape means a different piston. I have also requested a higher silicon content.

Instead of posting manufacturer claims, which we all know are difficult to prove, it is best to let the engine performance speak for itself. So that is what I intend to do.

Anyone who has one of these engines can post anything he wants to post, but I am trying to avoid any controversy. I certainly will not say that brand A is better than brand B. There are lots of good engines available and some people have definite preferences. They should run what they like and what works for them.

 

[Archie Stanton]

Exhaust is just under 180 degrees. Intake is just under 125 degrees. The problem with putting exact numbers out is that someone will say those number are no good, or that another brand's numbers are better. If I were to say that the exhaust was exactly 180 degrees, someone will measure their engine differently and make a big deal out of it, whether they can measure correctly or not.

Different numbers do not necessarily mean better or worse performance. You might like one brand in a mono and another brand in a rigger. Your experience is the most important measure of what kind of performance you will get out of any engine.

The head button chamber is a different shape and volume than the Cobra head button.

Rossi makes their pistons individually for each sleeve. They do not just make a batch of pistons and a batch of sleeves. A different sleeve shape means a different piston. I have also requested a higher silicon content.

Instead of posting manufacturer claims, which we all know are difficult to prove, it is best to let the engine performance speak for itself. So that is what I intend to do.

Anyone who has one of these engines can post anything he wants to post, but I am trying to avoid any controversy. I certainly will not say that brand A is better than brand B. There are lots of good engines available and some people have definite preferences. They should run what they like and what works for them.

Thanks

Sounds good to me

 

[julianconde]

where can i Purchase a engine,header,pipe and carb ASAP

 

[Al Hobbs]

You can get one from Jerry Crowther at Seaducer Boats, Troy Davis in California, Steve Winks in Australia (Wideboy Racing), Andrea Cavalli (Ready to Win Models) in Italy, Grahame Morgan in England, or send me a message and I can get one coming to you.

Al Hobbs

 

[Duck899]

Al Hobbs or wideboy or any of the people mentioned in the posts previous.....

 

[julianconde]

PM sent

 

[Jud]

I ran the A/A last weekend in Needles CA for the first time in a 10 years old A Hydro I had sitting around with an OPS in it. Bolted in the A/A a went to the untested. I ran a couple a tanks of fuel threw it and got the needle close. On sunday it was cold and rainy But we raced any way , the A/A ran great right out of the box with the head clearance at .006 with the A/A pipe at the stock setting . Won the first heat but the weather got worse so packed it in . The A/A ran better than i thought it would in the old boat ,made it look like i needed a bigger boat ,So been busy in the shop making sawdust. Hope to have a new boat in a week or so, will let you no how it goes. Thanks Al for promoting the Hobby like you do ,you will alwasy have our support here in Scottsdale.

Justin Hill and the rest of the Hill family.

 

[Rokieboater]

I ran the A/A last weekend in Needles CA for the first time in a 10 years old A Hydro I had sitting around with an OPS in it. Bolted in the A/A a went to the untested. I ran a couple a tanks of fuel threw it and got the needle close. On sunday it was cold and rainy But we raced any way , the A/A ran great right out of the box with the head clearance at .006 with the A/A pipe at the stock setting . Won the first heat but the weather got worse so packed it in . The A/A ran better than i thought it would in the old boat ,made it look like i needed a bigger boat ,So been busy in the shop making sawdust. Hope to have a new boat in a week or so, will let you no how it goes. Thanks Al for promoting the Hobby like you do ,you will alwasy have our support here in Scottsdale.

Justin Hill and the rest of the Hill family.

SUCK UP!!!!!!

Robert Holland