Magnum info

Stuka Stunt Main Forum · 33 of 33 known posts recovered

Dave Simons · Feb 25, 2004 05:59 PM

Can someone help out on this one, please. I'm in the process of trimming a rather porky Magnum. Lent to someone or lost the plans/instructions, so I dont know where the design CG is supposed to be. I would prefer a dimension of XXX aft of the root LE or ahead of the flap hingeline.

I figure that starting where the designer intended the CG would be sensible .... if all else fails RTFM!

I figure that somone out there in SSWland will have the info.

Thanks in advance,
Cheers, Dave

David Hoover · Feb 25, 2004 07:45 PM

#1 source

The manual says, "The Magnum should balance 3 5/8" from the leading edge of the wing at the fuselage.". Hope that gets you started. I have a significantly porky one as well but I'm amazed at how well it flies even carrying all the weight. Enjoy.

Best, Hoovie

Life is simple. Eat. Sleep. Fly.

Dave Simons · Feb 25, 2004 08:31 PM

#2 source

David,
Exactly the data I was looking for, many thanks! Say, I bet mines porkier than yours - how about 68 oz w/ST60?
Thanks again,
Cheers, Dave

David Hoover · Feb 25, 2004 08:41 PM

#3 source

Yer not even close! Have fun.

Best, Hoovie

Life is simple. Eat. Sleep. Fly.

builditright · Feb 25, 2004 09:49 PM

#4 source

go here to see the instruction book you should also be able to print them if you like

http://www.builtrightflyright.net/projects/MyCurrentProjects5intructionbook.htm

Thank You and God Bless
Walter Umland
aka / builditright
please visit my web
http://www.builtrightflyright.net

Dave Simons · Feb 25, 2004 10:04 PM

#5 source

Walter,
Many thanks, it's very generous of you to go to the trouble to make this information available - much appreciated.

Aw, c'mon Hoovie, how heavy? ... might make me feel better.

Cheers, Dave

David Hoover · Feb 27, 2004 07:14 PM

#18 source

Dave, If you check out http://www.clstunt.com/cgi-bin/dcforum/dcboard.cgi?az=read_count&om=5360&forum=DCForumID1 you can read all about it including the weight.

Best, Hoovie

Life is simple. Eat. Sleep. Fly.

ty marcucci · Feb 26, 2004 03:08 AM

#6 source

Today I finally received many back issues of Flying Models and lo and behold in one article it talks about the Magnum and the original had a four stroker in it. Do you per chance think that might be why it flew so well and all the others with two strokers just struggle to get in the air. Hmmmmm. I wonder.

Jim Pollock · Feb 26, 2004 07:46 AM

#7 source

Ty,

Shame on you, you saw mine fly - it didn't struggle at all!
T&L ST .51 powered too!

Jim Pollock

MikeC · Feb 26, 2004 01:20 PM

#9 source

A Sig Magnum should not struggle with a T&L ST51 up front, no matter what the weight. I believe the ST51 is one, if not the best engine for the Sig Magnum.

The only problem I have with my T&L ST51, is the last six or seven laps at the end of the pattern. Boy Howdy, Ya need to lean back and hold on.

Let's get together and burn some fuel.

Mike Clark
(MikeC)

Mikey · Feb 26, 2004 01:30 PM

#10 source

Mike,
Move the uni-flow vent closer to the end of the pickup tube inside tank. On most tanks the uni-flow vent is 3/8" from the end of the pickup tube. Change your's so it is 1/4" from the end of the pickup tube. By moving the vent closer to the end of the pickup tube the vent will stay coverd with fuel longer and it should cut the fast laps down to just a few.

Mikey

Mike Pratt

ty marcucci · Feb 27, 2004 08:56 PM

#21 source

Hi Jim. The only time yours slowed down was in high winds and others almost fell out of the sky, yours dropped into first gear and kept on chugging along. some of them are built way over weight due to too much paint I believe. Use Japanese tissue and three coats of clear, that'll keep'em light. Ha.

Mikey · Feb 26, 2004 11:43 AM

#8 source

>Today I finally received many back issues of Flying Models
>and lo and behold in one article it talks about the Magnum
>and the original had a four stroker in it. Do you per
>chance think that might be why it flew so well and all the
>others with two strokers just struggle to get in the air.
>Hmmmmm. I wonder.

Ty,
The Blue Magnum shown on the box had many different engines that were installed and flown at different times. The first was a St .60 (Big Art) that flew it great but I never really liked the feel of the St .60. It always seemed like they were too strong even with many head shims and low nitro fuel. This thing pulled so hard that after 5 or six flights I was beat. When I go flying I like to fly and really work at it. Just ask Bill Rich LOL.

As a foot note to the above statement the best St .60 that ever flew the Blue Magnum was one I borrowed from Wendy at one of the team trials. This engine was really ugly and covered with burnt on castor. While practicing one afternoon my flying partner John Davis (I really miss him) loaned me a Bolly 12-1/4" x 6-1/4" three blade and the Magnum came alive. This was a sweet setup and it was really fun to fly.

Next was the Merco .49. This was better but still not what I wanted, smooth but low on power. Then switched to the Merco .61 and it was not consistent at all and it just plain ticked me off.

Then the reworked 40 FP (yes that is correct a .40 FP) that engine was really smooth but again lacked the power needed in the wind (81 Nat's). It was not the engine that was the problem but the Magnum was too big and heavy (60 ounces) for the little engine.

Next a Saito .40 four stroke with a home made venturi was installed and flight testing began. This setup showed promise but again lacked the power needed in the wind. About this time Saito introduced a new engine called the .45 special with a high lift cam and higher compression head. This engine had much more power and handled the wind better. It also sounded really cool like it was relly pissed. Off to the Lake Charles Nat's with this set up just knowing I was going to really put an O'l Whoppen on some of the guy's. Well to make a long story short the heat (100 plus) and humidity (100 plus) in LC just killed it. We tried everything we could from 35% Nitro to more props than I want to count. It didn't have the power of a good Fox .35 and my score showed it. I had grafted a new nose on the model after a mishap practicing at home and could not switch back to the other engines during the Nat's. After arriving back home in Iowa the Magnum flew just fine with the Saito .45 S. So much for causing a stir at the Nat's with my 4-stroker (well maybe they were laughing at me behind my back LOL). The Blue Magnum was retired shortly after that and hangs from the ceiling to this day.

Mikey

Mike Pratt

ty marcucci · Feb 27, 2004 09:02 PM

#22 source

So, then, they lied in FM. Hmm, never believe everything you read in a magazine. I have a new in the box Magnum kit and have recently aquired an ST.51, so guess what?? But then I also have a new in the box Saito .56 4s, so I am torn which to use. Oh, yeah, really torn up. Ha. I'll use both.

Jim Pollock · Feb 27, 2004 09:09 PM

#25 source

LAST EDITED ON Feb-27-04 AT 09:16 PM (CDT)

Ty,

If it's coming out porky probably the 4S would be better because at a lighter weight I think the 4S would make it too nose heavy.

Also, the folks at SMDC decided to cancel the job that I had applied for. ugh!

Jim Pollock

SteveB · Feb 26, 2004 01:52 PM

#11 source

Ya'll have convinced me. I'd like to get a Magnum for my new ST. 51 that I bought last week. Only problem is, I can't seem to find a place that sells the kit. It doesn't even show up on Sig's website.

Anybody got an idea?

LNeumann · Feb 26, 2004 09:46 PM

#12 source

>Ya'll have convinced me. I'd like to get a Magnum for my
>new ST. 51 that I bought last week. Only problem is, I
>can't seem to find a place that sells the kit. It doesn't
>even show up on Sig's website.
>
>Anybody got an idea?

SIG discontinued the model. Put a wanted ad in the classifieds here. Several have been sold there recently. Another might turn up.

Leonard Neumann

Leonard Neumann

ty marcucci · Feb 27, 2004 09:05 PM

#23 source

Got to laugh here. I made out like a bandit at a local RCRC (Rocket City Radio Controllers)club "swap" meet three years ago. Picked up a new Magnum and a Brodak bellcrank in the kit for a measley $65.00 US dollars. The RC flyer was real torn up about asking so much for it. I had to run outside for a few moments to keep from laughing in his face.. I came back in and very somberly (great acting on my part) parted with my 65.00. Oh the joy of going to an all RC swap meet.

Brett Buck · Feb 26, 2004 10:02 PM

#13 source

Sheldon's Hobbies had one last week. They advertise in all the mags.

Brett

MikeC · Feb 26, 2004 10:06 PM

#14 source

Yes, Watch Ebay, they show up about three time a month.

Mike Clark

C/L Gee Bee · Feb 26, 2004 10:34 PM

#15 source

Mike Lauerman

Heck, I thought that was a heck of an airplane. If discontinued, do y'all think Walter Umland or Larry Richards might pick it up?
Fascinating story on the Engine Tree, by the way...Thanks, Mikee
LOVE those 4-strokers, wish that had worked out!

Mikey · Feb 27, 2004 04:23 PM

#16 source

My first experience with St .51 was when a good friend from Des Moines wanted to build a Magnum. I had heard about how good the St 51's were and told him to get one from T & L or Randy Smith and I would help him build it. He decided on the Randy Smith ST .51 and ordered the engine. Meanwhile he started building his Magnum. He would bring it Sig every week and I would inspect his work and every week he would take it home and redo something I didn't like. Nothing big, just a bunch of little things. When he was finished had a really pretty Magnum with twin rudders, wheel pants that matched the rudders, and a dope finish the tipped the scales at 60 ounces.

I took us only four or five flight to get it trimmed and what a dream it was to fly. The St .51 had more than enough power to fly in any conditions and was rock solid. This was a great combination of airframe and power plant.

Mike Pratt

Bill Little · Feb 27, 2004 05:46 PM

#17 source

Hi Mikey,
Just wanted to say what a great all round plane the Magnum is. Ya done good!
Wish Sig hadn't discontinued it..... We have one, mostly scratch built, foam wings, and a little cosmetic changes to it. Really pretty much to the "plans", though. Flys like a dream on the ST 51!
It has had a royal 45, and VF 40 and 46 on the pipe, but now a 51 is back in it.
Thanks!
Bill <><

Just an Old Advanced flyer.

Jay Williams · Feb 27, 2004 08:40 PM

#19 source

I thought Tower was selling them?

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXFV87&P=7

Is this the same ST51 everybody is talking about or do I have the wrong one?

Jay

treat each day as if it were your last, because one day, it will be.

Bill Little · Feb 27, 2004 08:47 PM

#20 source

LAST EDITED ON Feb-27-04 AT 08:50 PM (CDT)

Jay,
You got the right one. AFAIK, that's the only ST 51 that has been made in the last 10+ years. The first batches of this version were made in Italy and had different timing I understand..... And the current (made in China) have a different sleeve for the C/L and R/C versions. When I bought my first one back in '93, it was an R/C engine, and I sent it straight to The Layster. Since I no longer have that one, I'll have to send my new one to Tom!
Bill <><

Just an Old Advanced flyer.

Alan Hahn · Feb 27, 2004 09:08 PM

#24 source

The Italian-made ST51 also had a different sleeve (or part number if you look at the parts sheet) from the RC version. I think the Chinese versions are just the same as the original Italians.

Alan

Bill Little · Feb 27, 2004 09:13 PM

#26 source

LAST EDITED ON Feb-27-04 AT 09:15 PM (CDT)

Thanks Alan,
I knew the "new" ones do, never looked at the other one's parts list! LOL!! It went to Tom before I ever saw it.
Also, as to the G-21 ST 51, never had one, are they closer to the 46 or 60 in size? I *think* they are on the 60 case??
Bill <><

Just an Old Advanced flyer.

Steve Helmick · Feb 27, 2004 11:53 PM

#28 source

LAST EDITED ON Feb-28-04 AT 00:01 AM (CDT)

>Thanks Alan,
>I knew the "new" ones do, never looked at the other one's
>parts list! LOL!! It went to Tom before I ever saw it.
>Also, as to the G-21 ST 51, never had one, are they closer
>to the 46 or 60 in size? I *think* they are on the 60
>case??
>Bill <><
>
>Just an Old Advanced flyer.

The "G.51" is the 3rd .51 that ST has made. First came a plain bearing, along with the plain bearing .45. They didn't come into the country very long, a few years. Then the ST .60bb, .56bb and .51bb. These are all the same casting as the .60bb, but on the .51, the fins were turned (or maybe cast) smaller diameter, smaller head, etc. The "G.21 case" only went as big as the .46, except for a few guys like Rabe. The Mutant Magnum (Dixon's "Magnum Plus")will shortly be fitted with a Tom Lay G.51 I bought from Tower in January. Tom sez the Chinese engine isn't changed at all, other than "Hecho en China" on the backplate, and of course the warning lable on the package, that it could cause cancer in California. I just ordered another one, which I plan to plug the boost port on. They're down to $90. Steve

http://www.nwskyraiders.com/index.html

Bill Little · Feb 28, 2004 09:24 AM

#29 source

LAST EDITED ON Feb-28-04 AT 09:25 AM (CDT)

Thanks, Steve!
As to the G vis a vis G21, didn't know that either, but used that designation so that someone "in the know" (like you) would know what I was talking about! Thanks for the answer, I am glad to learn.
Thanks, again
Bill <><

Just an Old Advanced flyer.

Steve Helmick · Mar 01, 2004 09:56 PM

#30 source

LAST EDITED ON Mar-01-04 AT 10:05 PM (CDT)

>Thanks, Steve!
>As to the G vis a vis G21, didn't know that either, but used
>that designation so that someone "in the know" (like you)
>would know what I was talking about! Thanks for the answer,
>I am glad to learn.
>Thanks, again
>Bill <><
>
>Just an Old Advanced flyer.

Some folks call the ST .51 > .60bb case the "V" series, but the ads always simply called them the ST .60bb, etc.

The real "G" series "big block" was a real heavy racing & R~C engine, built with either baffled or flat topped pistons, like the G.21 .40. Two basic "G" crankcase castings, the G.40 and the G.61/.65/.7?. I ran a G.65 in "C Speed"...not a great engine. All subsequent Super Tigre 10cc engines were ".61's", so if somebody says they have a ST .61 for sale, you don't want it for stunt.

The G.40 was another husky hunk of metal. My OFB Dave Woodcock (now my Dentist) set a Navy Carrier record with a G.40 when Class II came in. The G.40 was dropped quickly, tho the bigger ones went on for quite a few years as R~C engines with front intake. The G.40 only came as a rear intake, AFAIK.

If anybody knows how the COMO engines fit in the scheme, I'd be interested. I think World Engines didn't have enough money to really market ST's effectively, and stock parts. My belief is that Indy R/C brought in ST's under the COMO label, and they were mostly upgrades with Perry Porting, and had the concave head fins. I wasn't very interested then, having waited two years for backordered ABC P&L's for the G.65

While I'm destroying Dave's Magnum thread, does anybody put heavy metal inserts into ST .60bb cranks? Steve

http://www.nwskyraiders.com/index.html

Mel Duval · Feb 27, 2004 09:25 PM

#27 source

Hi Steve,
Email me at .

later,
Mel D>

Rick · Mar 03, 2004 11:56 AM

#31 source

LAST EDITED ON Mar-03-04 AT 11:56 AM (CDT)

I have been tempted to buy one of the ST 51's from Tower. The price has gone down from somewhere around $109 to $89 but I hadn't heard if the quality had changed since they started being produced in China. If they are the same engine that they were a few years ago when they were being produced in Italy the $89 dollar price tag is pretty appealing. Does anyone know how they run straight out of the box or is a rework a must?

Rick Henry

Alan Hahn · Mar 03, 2004 02:52 PM

#32 source

I know of people who ran the Italian version stock (except fot the muffler of course). By Italian version, I mean the 51 that the current Chinese version as a copy of.

Alan