William Robison

My Feedback: (3)

Gnome:

Just a little more. If the engine pictured in your avatar is the one you have then you have the metal rocker boxes. If you painted the cylinders while you had it apart then hopefully you were careful to make the paint as thin as possible. A good thin black paint helps the cooling, but if too thick it can worsen the tendency to overheat.

Bill.

Ram-bro

My Feedback: (101)

I have a coupla questions for the experts here, What is the horsepower rating for the asp 400 5 cylinder radial? Next question is how does a 4 stroke equate to a 2 stroke engine...meaning is a 4.0 5 cylinder as strong as a G62?

Kmot

My Feedback: (24)

The ASP/Magnum AR400 radial engine is rated at 5.5 kilowatts of power @ 7250 rpm. 5.5Kw is equivalent to 7.375 horsepower. The AR400 swings 18x12 - 24x8 props. Weighs 98 ounces.

The G62 is rated at 4.75 horsepower and swings 20x6x10 - 22x6x10 props. Weighs 82 ounces with muffler.

the Gnome

Hey Bill, nice to meet somebody who knows Mr. Furmanns secrets too, we are not that many, it's a bit like wales meeting in the ocean.

I'm happy You have that much experiance with TP engines, You must have had some of them, very interesting facts! My engine has the serial number B9C005, it has the metal rocker boxes, the billet master rod and steel sleeve cylinders with black anodized alloy fins. I have set the valve timing to the following:

exhaust opens: 40° before BDC, closes: 8° after TDC, inlet opens: 8° before TDC, closes 25° after BDC

So You see what I ment with the symmetrical overlap. As I remember, I could touch the crankcase emediately after the engine stops, I ran it at various speeds for about 10 minutes before, so I cannot say it overheats, but I will fire it up again during the next days, perhaps I remember nit right.

I thought the carburettor may be too big, it doent has a sleeve in the big OS carb, I had this problem with my ST710, Mr. Seidel did forget the sleeve in the carburettor.

By the way, a friend of mine is working at the engine devellopment stuff at Volkswagen, today plastic has impressive capabillities, the make the intake manifolds even for the new 1.4 litre combined supercharger / turbo engine with 1.8bar boost pressure at some 200° Celsius intake air temperature out of plastic!!!


Holm und Rippenbruch,

Jens

Ram-bro

My Feedback: (101)

thanks Kmot.I am conssidering sticking the AR 400 in a Zirolli Skyraider and just wasnt sure which route to go...the G62 or the AR 400. I have always been under the impression that a 4 stroke is not as strong as a equivalent size 2 stroke....

the Gnome

Hey Ram-bro,

I really cannot believe that the AR 400 has more or adequate power compared to a G62. Normally a 2 stroke has more power than a 4 stroke because it makes twice the combustion phases. The real compression rate is normally less than of a 4 stroke (because of the ports), but it can't make a bigger difference than the more combustions.

Kmot,
do You have Your data from own experiance? May be I'm wrong and a G62 is a real bad engine, but perhaps Magnum lies with their power output data. A gas engine has also normally more power than a methanol one, gas has mor internal energy than alkohol.


Holm und Rippenbruch

Ram-bro

My Feedback: (101)

I saw the same numbers on the ar 400 but you bringup some food for thought. So are horsepower ratings honest as listed by the manufacturers? So is your contention then is that the AR 400 does not match up well to the g62?

w8ye

My Feedback: (16)

Don't put very much faith in published HP figures.

What's important in the post up the way is what prop the engine will swing.

Figures don't lie but lier's figure.

the Gnome

Yes, Yes, Yes, I agree, have a look on the homepage www.toni-clarc.com , they are, as I know Mr. Reintsch personally, very reliable. To their claim the G62 swings a 24x10 at some 6400rpm, and so a 24x8 even higher. As the 24x8 is the largest prop Magnum sais for the AR400, I don't think that it can swing it at peak rpm.
Even the Seidel ST710 don't has as much power as the G62, to my experiance it swings a 24x10 at some 5500rpm.

Kmot

My Feedback: (24)

My post had figures that I found published by Just Engines, Inc in England, and Horizon Hobby in USA.

the Gnome

May be, the AR400 is a real strong going engine, perhaps could somebody, who is flying it, tell us the prop and rpm of his engine, would be very interesting.
Perhaps we should collect those data of flying radial engines of the different makes, so that we can really choose the right radial that fits the new model. One of us could collect the data sent by email and then post the complete collection, what do You think?

Kmot

My Feedback: (24)

Jens, that is a good idea. Perhaps we can start with your engines first?

I just was doing some research and found a site in Germany that lists the power output of the FS400AR as 4.08kW and 5.5PS. What is PS? Horsepower?

http://www2.produktinfo.conrad.com/d...e-en-fr-nl.pdf

William Robison

My Feedback: (3)

Tom:

"PS" is a European measure that almost corresponds to horse power, as I recall one PS is about 1.1 bhp. But 4.08 KW is 5.49 bhp. 746 watts delivered is 1 hp.

Bill.

Ram-bro

My Feedback: (101)

the conversion chart I have says 1.341kw=1hp

William Robison

My Feedback: (3)

RB:

That's the reciprocal. Divide that 1.341 into 1 and you have the 746 Watts. Some conversion formulae are written to use the reciprocal, that may be where you got it.

Bill.

Ram-bro

My Feedback: (101)

so what does it all mean in the real world?[]

William Robison

My Feedback: (3)

RB:

In our world it doesn't really mean anything. RPM with a given prop and fuel is a much better comparison.

Bill.

Ram-bro

My Feedback: (101)

Kmot, thanks for the German website. I got more info there than I did with the Magnum engine. There is a guy on the east coast selling these motors NIB on ebay. They are going for under $700 or %50 less than what the overseas market is selling them for.

Kmot

My Feedback: (24)

Ram-bro: yup, that Conrad manual is the shiznit!! Must have been made in-house special by them.

Kmot

My Feedback: (24)

Bill, did you see the prop/rpm chart in the Conrad manual?

Propeller Rpm
18 x 10 8200-8400
18 x 12 7200-7400
18 x 14 6800-7000
20 x 8 7900-8100
20 x 10 7000-7200
22 x 8 6900-7100

Ram-bro

My Feedback: (101)

Kmot , when you look at that chart, are you looking for max rpm for greatest horsepower or what?, or is it different for 2 strokes vs 4 strokes?

William Robison

My Feedback: (3)

Tom:

Using Pe Rievers' "Prop Power" sheet I get these numbers:

18-10 at 8400 rpm, 3.36 hp
18-12 at 7400 rpm, 2.75 hp
18-14 at 7000 rpm, 2.72 hp
20-8 at 8100 rpm, 3.67 hp
20-10 at 7200 rpm, 3.22 hp
22-8 at 7100 rpm, 3.62 hp.

All are using the upper limit from the chart, and a prop factor of 1:1. I didn't notice Conrad mentioning a brand, if he did we might refine the numbers a bit.

Regardless, looks like the engine prefers the 8" pitch.

Bill.

Ram-bro

My Feedback: (101)

Bill, thats great. So where can a guy get this prop chart? Alsosince this shows the horsepower rating as just about 1/2 of what is advertised what would be the true horsepower ratings for the G62? It looks like the power of the AR 400 would be marginal at best and I should stick with a G62 or larger. That sucks.....

Kmot

My Feedback: (24)

Ram-bro: We need to compare apples to apples. Let's find a chart that shows how many rpm a G62 turns with a 22x8, for example.

the Gnome

As I said, have a look on the website www.toni-clark.de ; there is a power to rpm diagram for the G62, with the normal G52 silencer it has about 3.9hp at 7100, so it is a little better than the AR400. It depends on the silencer, the G62 can perform double the power with a megaphone style silencer.

By the way, the difference between PS (DIN PS), bhp an SAE hp is only the method of measuring it. DIN PS is measured with all the necessary equipment (silencer, dynamo, air cleaner etc.), I think bhp is measured witout any equipment (no silencer etc.) its the best performance of an engine, SAE hp, if I'm right, is measured with dynamo and air cleaner but without silencer. This is with the big engines. So for us it doent means any difference.