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Seidel 7-70 radial: Help me decide!

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Seidel 7-70 radial: Help me decide!

Old 07-31-2010, 04:57 AM
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Teus
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Default RE: Seidel 7-70 radial: Help me decide!


ORIGINAL: abufletcher

And can you imagine what a stunning model it would make with a 9.5'' diameter radial engine!

Yes I can

Photos and movie are made back in 2005 with my first digital camera so the sound is not that good.. Model is fitted with the old type 770 Seidel. She made only 2 flights so far and the model has now a new owner who fitted the new UMS Seidel. Due to circumstances you missed the model at the Dutch Dawn Patrol.

[youtube]http://www.youtube.com/watch?v=OGbhMF8ZENc[/youtube]

[youtube]http://www.youtube.com/watch?v=thIeI_Llz4k[/youtube]
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Old 07-31-2010, 05:44 AM
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Default RE: Seidel 7-70 radial: Help me decide!

Those Dutch guys have all the fun! [] But that engine does look a tad big on that model. What scale is it? But it's REALLY nice to see a Seidel actually being used in a flying model.
Old 07-31-2010, 05:49 AM
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Default RE: Seidel 7-70 radial: Help me decide!

I believe it is 1/4 scale. I check it out and let you know.

Teus
Old 07-31-2010, 09:11 PM
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Default RE: Seidel 7-70 radial: Help me decide!

Surely by now you have seen this from OS...maybe a little pricey....

http://www3.towerhobbies.com/cgi-bin...?&I=LXZVB2&P=0

And then there is the Moki and the FW Pup....from Vogelsang Aeroscale....

http://www.vogelsang-aeroscale.com/jwpup.html

After nearly 40 years in aviation the only sound that make me run out and look is the sound of a radial..and maybe a Merlin or Allison.....
Old 08-01-2010, 02:01 AM
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Default RE: Seidel 7-70 radial: Help me decide!

ORIGINAL: V2PLUS10
Surely by now you have seen this from OS...maybe a little pricey....
Aside from costing 4 times the price of the Seidel 7-70, the new OS's design just doesn't give off an "old-timey" vibe. I think for me, it would be either the Seidel or no radial at all.

That looks like a great kit and the high degree of "pre-fabrication" (e.g. pre-finished struts and riggings wires) would probably appeal to many...though not necessarily to me. But then if you're going to build a kit, why not really have it be a kit rather than just a box of wood?

On thing that's interesting is that they say it would fly with either the Moki 150 or a ZG 62 with reduction gear. But I'm confused about the "size" of the Seidel 7-70. I would assume that either the 7-70 or the 9-90 could fly this model. But the Seidel website lists the 770 as 70ccm and the 990 as 90ccm. And I've thought of both as being more or less comparable to the Zenoah 62.

BTW, also notice that the cost of the ZG62 + reduction gear is MORE than the Seidel.
Old 08-01-2010, 02:10 AM
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Default RE: Seidel 7-70 radial: Help me decide!

Teus, didn't the GIII have an open bottomed cowl? That's what I remember from my recent trip to the RAF museum.
Old 08-01-2010, 04:14 AM
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Default RE: Seidel 7-70 radial: Help me decide!

There were different versions and one was the Anzani powered version without a cowl and with an exhaust collector ring like my friend used on his Seidel.

The Anzani powered G3 is in the RAF Hendon museum.
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Old 08-01-2010, 08:40 AM
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Default RE: Seidel 7-70 radial: Help me decide!


ORIGINAL: Airwarrior

Great looking plane, but Mr. Pilot doesn't look too healthy! Tell that chap to straighten up!
Mr.Pilot is anxiously awaiting the moment a DH-2 or N11 dives down on him. Mr.Pilot realizes what crappy performance his mount has and constantly scans upward which has caused this 'skyward glance affliction'! The Proctor Eindekker is neat looking, though! Can't wait to build mine!
Old 08-01-2010, 09:57 AM
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Default RE: Seidel 7-70 radial: Help me decide!

I agree that the cost of the OS and Moki's are high when you compare them to the cost of the Indian made Seidel. The old Technopower engines and the Seidel really do have the "look" of the old radial.

What has always stopped me(aside from cost!), is the prop speed/rpm. Most the WWI rotary engines had an operating rpm of around 1200. This is what looks and sounds realistic. Somewhere I've seen a video of a large model Pup with the reduction gear, and the prop rpm is fantastic....but the sound is high pitched two-stroke...by comparison, the sound of a model radial is wonderful, but at flight rpm the romance goes away, as the sound of that high reving prop overshadows the sound of the exhaust.

On one version of the the R-4360, max takeoff rpm was 2700, the prop was run through a 0.375:1 reduction, which gives a prop rpm of about 1012. Climb and cruise rpms would have been much lower.

I would love to have something with a radial engine just the same...though a Pup may be lacking the wow factor, that would still be my choice.

Realism is elusive.

Randy
Old 08-01-2010, 10:12 AM
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Default RE: Seidel 7-70 radial: Help me decide!

ORIGINAL: V2PLUS10
The old Technopower engines and the Seidel really do have the ''look'' of the old radial.
I agree. I've also decided that the 7-cylinder Seidel 770 somehow looks more "scale" that the 9-cylinder 9-90 in terms of looking the part on a WWI model with a 9-cylinder rotary. The 990 is just too "busy" looking without enough space between the cylinders. Still, the Seidel is never going to be as scale in appearance as a top-notch dummy. One plus though is that, while a dummy engine has to sit in front of the engine which puts it too far forward in the cowl, one of these radials would sit right in the middle of the cowl where it's supposed to be.

What has always stopped me(aside from cost!), is the prop speed/rpm. Most the WWI rotary engines had an operating rpm of around 1200. This is what looks and sounds realistic.
The Seidel has an RPM range of 1000 to 6000 (with a 22 inch prop) and on a 1/4 scale Pup, for example, you'd probably only end up using about 1/4 throttle so you might very well get a pretty "scale" range of RPMs. But of course a radial isn't a rotary and doesn't sound like one. And in the end, it seems a bit silly to spend this much money for a "nice sound." For me the primary reasons for buying a Seidel would be:

1. The mock realism of having a functioning "round" engine (though still not a rotary and still not exactly scale).

2. The ability to swing a scale diameter prop without the expensive (and sometimes fussy) reduction gear.

Realism is elusive.
And "real" to one person isn't necessarily "real" to the next.
Old 08-01-2010, 10:24 AM
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Default RE: Seidel 7-70 radial: Help me decide!

The 22" prop you mention is quite close to scale diameter for most quarter scale rotary engined aircraft. The drive reduction units you often mention turn props in the 30 inch range and some larger, closer to 1/3 scale and most ofen used in that size aircraft. The Mick Reeves unit and a G62 combined are still less than the Indian Seidel.
Doc
Old 08-01-2010, 10:35 AM
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Default RE: Seidel 7-70 radial: Help me decide!

Awwww come on Don, now your beginning to talk your self out of it........[sm=tongue_smile.gif]
Old 08-01-2010, 10:38 AM
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Default RE: Seidel 7-70 radial: Help me decide!

But he has almost got me talked into it!! 995 euro is about 1300 USD hmmmm......we spent that much on a section of fence this spring....!!
Old 08-01-2010, 10:43 AM
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Default RE: Seidel 7-70 radial: Help me decide!

And here's the glow driver....

http://www.sonictronics.com/xcart/pr...cat=308&page=1
Old 08-01-2010, 10:44 AM
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Default RE: Seidel 7-70 radial: Help me decide!

Randy,
As long as you realize it is a questionable copy of a Seidel. The guys remarks about receiving them dirty makes me wonder. A thousand dollar + paperweight is expensive artwork!
Old 08-01-2010, 10:46 AM
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Default RE: Seidel 7-70 radial: Help me decide!

ORIGINAL: Reg Hinnant
Awwww come on Don, now your beginning to talk your self out of it........[sm=tongue_smile.gif]
I like to talk myself into and out of any purchase at least ten times...before going ahead and buying!
Old 08-01-2010, 10:56 AM
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Default RE: Seidel 7-70 radial: Help me decide!

Well, you have talked me into believing that you really need one to be satisfied......

We would all enjoy watching you get immersed in the installing, care & feeding of the little beast.
I can’t think of a better caretaker to document that progress to a successful conclusion
Old 08-01-2010, 11:02 AM
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Default RE: Seidel 7-70 radial: Help me decide!

Seems one of the issues with the small radials is getting an even distribution of the fuel mixture to each of the cylinders. You can have one or more hot cylinders with the others at normal temp. The OS pictures show a built in diffuser. The smaller Moki's can benefit from an add-on diffuser, but I don't remember if it's factory or after-market.

Reg, you had an original Seidel....did you ever fly it?

Randy
Old 08-01-2010, 11:49 AM
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Default RE: Seidel 7-70 radial: Help me decide!

ORIGINAL: Reg Hinnant
As long as you realize it is a questionable copy of a Seidel. The guys remarks about receiving them dirty makes me wonder. A thousand dollar + paperweight is expensive artwork!
Maybe. But those same guys are probably also the guys who just plan to put them into a glass cabinet. You'd hear the same sort of stuff from the "Leica collectors" about the M6TTL being "a piece of junk" compared with the M6. And these would the guys seemed never ever to do any actual photography with their precious Leicas.

Seidel states that it test runs every engine...and it fact the "manual" that Teus uploaded actually says they "test fly" every engine (though this could be an English translation error) and states that if the buyer intends just to use the engine for display they can request that the engine isn't test run. BTW, my RCV engine arrived covered in oil...and that's probably a good thing.
Old 08-01-2010, 11:59 AM
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Default RE: Seidel 7-70 radial: Help me decide!

I just got to see a Gnome 50 HP run at Oshkosh, Friday, and I was kind of surprised at the sound. It was loud, but not too loud; you could hear the whirl of the cylinders as much as the exhaust. The exhaust stroke happens at the same point in rotation, so it kind of sounds like a single cylinder with a lot of mechanical noise going on with the odd misfire. It sounded like a single 4 stroke with no muffler at 1/3 throttle with a bunch of mechanical clacks and a house box fan blowing. It does not have the pack of Harleys sound like a radial. It also had the same sound quality of the cars at the same time, too; the sound is of Model T not modern smooth Ferrari. The smell was classic for a modeler; it smelled exactly like a Cox .049 running Cox fuel.
Old 08-01-2010, 12:09 PM
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Default RE: Seidel 7-70 radial: Help me decide!

Seeing, hearing, smelling and maybe getting a little oily from a rotary engine is on my to do list......I am consumed with envy....

Randy
Old 08-01-2010, 12:33 PM
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Default RE: Seidel 7-70 radial: Help me decide!

ORIGINAL: TFF
It does not have the pack of Harleys sound like a radial.
That's an apt description of the sound that modelers seem to love about the Moki and the big Seidels. It sounds big and mean, just like you'd want a WWII warbird engine to sound. But the WWI rotaries didn't sound like that. In fact, most of the time they sound like an engine just about ready to cut out, because of course that was the only way to control the speed.
Old 08-01-2010, 02:38 PM
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Default RE: Seidel 7-70 radial: Help me decide!

Your right on the money TFF.
You guys really should purchase Hansen's DVD on Areodrome 92 & 94 and his ones on the filming of Young Indiana Jones. They were there at Frank Ryders museum specificly to get the aircraft sounds correct.
The old rotarys were smooth and had a hissing sound along with the exhaust. They do not sound like a radial.
Done Coe with his Pup and a Laser V twin that had the exhausts ending with a narrowed tip (ah la old Harley fish tail exhaust tips) came close with a hissing sound along with the exhaust sound. See his build thread.

Randy, I did not put my Seidel in a model. I had decided that it was not that suitable in a WW1 model & was waiting for Jerry Nelson of Nelson Hobby Specialties to finish his kit of the Meyers OTW. I think it would be more appropiate in a "between the wars" A/C or something that had a true radial engine.
Sorry Don........
Old 08-01-2010, 07:12 PM
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Default RE: Seidel 7-70 radial: Help me decide!

ORIGINAL: Reg Hinnant
Randy, I did not put my Seidel in a model. I had decided that it was not that suitable in a WW1 model & was waiting for Jerry Nelson of Nelson Hobby Specialties to finish his kit of the Meyers OTW. I think it would be more appropiate in a ''between the wars'' A/C or something that had a true radial engine.
Sorry Don........
It's what I've said all along...if you're aiming for absolute scale perfection then an absolutely scale perfect dummy will look better than a Seidel. But very VERY few WWI seem to have that level of dummy engine. And if you're after "scale sound" you bound to be disappointed.
Old 08-01-2010, 07:49 PM
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Default RE: Seidel 7-70 radial: Help me decide!

Let's have another look. As I said, I think the 7-cylinder actually looks a bit more "mock-scale" than the 9-cylinder. Maybe 18 rocker rods is a bit much. And I think the all "silver" cylinders of the newer Indian engines might actually be better suited to WWI models.

But really, the main reason is still to be able to use fly with a scale diameter prop. The Seidel 770 is designed for a 22" prop while a G26 turns a 16" prop.

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