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1/2 A building. / Re: Nylon firewall for Cox .049

« Last post by Mark Mc on Yesterday at 03:43:34 PM »

Quote from: 944_Jim on May 02, 2024, 03:10:03 PM

Even 1/8" tomato crate wood...it's only 1/2A. A reasonable Cox facsimile could be done.

Only 1/2A? Only 1/2A??? The most noble and sincere representation of youthful modelling in the annals of history?

ONLY 1/2A?!?!?

Engine set up tips / Re: O.S. Max-s 35 wants to shut off?

« Last post by Dan McEntee on Yesterday at 03:38:25 PM »

Quote from: Colin McRae on Yesterday at 02:15:44 PM

I don't have much experience with idle bar glow plugs.

I happen to have this idle bar plug, but not sure of the manufacturer or heat range. I saw a picture of a Zinger plug and it looks very similar based on the electrode tip being pointed. I also believe K&B made the Zinger plugs once upon a time.

The plug is a long-reach idle bar type. Can anyone please let me know if they know the manuf and heat range?

I will try it out on my OS Max-s 30 next time I am out flying my Banshee.

Thanks in advance

To ID an old glow plug you almost need a new in package example to match it up with. Heat range is a function of the size of the hole that the coil is in, and how heavy the coil wire is along with how many coils. A glow plug works from catalytic reaction with the alcohol in the fuel. If you have a bigger hole to hold more fuel and bigger wire you have more catalytic reaction and a hotter glow that lasts longer. get in the habit of looking at the business end of the plugs you have and just make a mental not of what you see. I like the idle bar because it give carbon some place to grow and keeps debris off the coil. Many plugs are made by the same manufacturer, and they produce the plugs to the specifications and "look" that the customer desires, so in effect, you could have three old plugs right next to each other, and even though they may look different, they may be the same plug!
Type at you later,
Dan McEntee

Open Forum / 2024 US Nationals Stunt Qualification Rounds Circle Seeding

« Last post by Howard Rush on Yesterday at 03:11:47 PM »

Here is circle seeding for the 2024 stunt Nats. I did it using the same seeding formula that was used for previous stunt Nats. The seeding formula is based on Open, Expert, and Advanced Nats placing for the last 10 years. US team members not attending the Nats during a world champs year are included, ranked the same as Open Nats winners. I attached a copy of the seeding spreadsheet. I put the seeding into the Nats stunt tabulation program. The tabulation program is too big to attach here, but I'll send it to anybody who wants it. I encourage everybody to look at these spreadsheets and critique them. Here are the top 30 seeds:

1 Orestes Hernandez
2 David Fitzgerald
3 Paul Walker
4 Derek Barry
5 Howard Rush
6 Kenny Stevens
7 Todd Lee
8 Joe Gilbert
9 Brett Buck
10 Joseph Daly
11 Robert McDonald
12 James Mills
13 Matthew Colan
14 Matt Neumann
15 Chris Rud
16 Michael Schmitt
17 Chris Cox
18 Michael McHenry
19 Bob Hunt
20 Crist Rigotti
21 Steven Daly
22 Bruce Jennings
23 Dan Banjock
24 Tom Luciano
25 Dennis Adamisin
26 William DeMauro
27 Steve Fitton
28 Richard Oliver
29 Vincent Bodde
30 Don Cranfill

For the top 20 in Open and Advanced for the last ten years, first place gets 20 points, second place gets 19, and so on. US Team members who were out of town for the WC get 20 points each. Scores get multiplied by 10 for 2023, 9 for 2022, and so on. Advanced scores are then multiplied by .5. Richard Huff's score includes both his Open and Advanced placings, for example. I combined the Expert and Advanced placings for 2014.

Top score is seeded #1. Guys who haven't placed in the top 20 in either Advanced or Open in the last ten years are unseeded. Their assignment to one of the four groups for qualifying rounds is done by random draw.

The tabulation program tosses out seeds that are not entered at the current Nats and moves those who are entered up to fill in gaps. For example, if Orestes doesn't show up for this year’s Nats, the tabulation program will bump everybody else up a notch.

This seeding is only used to distribute contestants among circles for qualifying. It might make the circles more uniform, but it has little effect on the outcome of the contest. Seeding is not an indication of one's worth as a person, which is obvious for four cases above. Here is a crude analysis I did on the effect of Nats qualification rounds seeding: http://stunthanger.com/smf/open-forum/nats-seeding/

Although seeding has little effect--none at all on the top handful of fliers-- using a formula published in advance removes any arbitrariness about circle assignment.

Oops, modified to update some dates.

Open Forum / Col. Peck's Barracuda

« Last post by Dennis Saydak on Yesterday at 02:55:44 PM »

Here's a picture of my Barracuda model as far as I got with it. Unfortunately because of long term mobility problems I recently decided to hang up my C/L handle for good. I donated the Cuda to a good friend last week who is a master painter. He intends to paint it; and if all the stars align it may even be at the US Nationals this year. It's a very unusual design and as far as I know only a couple of Cudas were built.

Engine set up tips / Re: O.S. Max-s 35 wants to shut off?

« Last post by Colin McRae on Yesterday at 02:15:44 PM »

I don't have much experience with idle bar glow plugs.

I happen to have this idle bar plug, but not sure of the manufacturer or heat range. I saw a picture of a Zinger plug and it looks very similar based on the electrode tip being pointed. I also believe K&B made the Zinger plugs once upon a time.

The plug is a long-reach idle bar type. Can anyone please let me know if they know the manuf and heat range?

I will try it out on my OS Max-s 30 next time I am out flying my Banshee.

Thanks in advance

AS TIME GOES BYE / Re: Hobby shops in L.A. area?

« Last post by Dennis Saydak on Yesterday at 02:00:37 PM »

Back in the 70s I made two vacation trips to California. I visited several shops in the LA area as well as one in Frisco. The one in Frisco was difficult to get to because of the double parked cars blocking access to it. The LA area HS that really impressed me was Tony and Addie Naccarato's shop in Orange, or was it Ontario? These folks were super helpful and friendly. I was very impressed with a large multi-engine model hanging from the ceiling. IIRC, it was the DC6 airliner that was featured on the cover of F.M. magazines.

Open Forum / Re: Balsa Safari

« Last post by Steve Dwyer on Yesterday at 12:29:47 PM »

Garage sales are big head turners for me as well. It's always good to have a few extra bucks with you if you pass by a GS to quickly brose what's there. The best opening question is "have any tools or hardware for sale". You never know what you'll find, it's worth a 5 min stop anytime.

Open Forum / Re: Balsa Safari

« Last post by Rusty on Yesterday at 11:04:11 AM »

I'll tell you another good place to get things that are helpful is estate sales. I go to estates all the time. About 3 weeks ago I went to one and they had model airplane stuff. I bought a good OS 52 four stroke, 3 feet of fuel line, exacto knife, heat gun, 3 foot metal ruler, 1 foot ruler, electric motor, esc and servo, ALL for $7.00.

Other sales I have bought sand paper, drills, band saw, dremel tools, soldering irons, etc.

You guys should try them too.

Rusty

Engine set up tips / Re: O.S. Max-s 35 wants to shut off?

« Last post by Ken Culbertson on Yesterday at 10:01:53 AM »

Quote from: Colin McRae on May 02, 2024, 11:45:32 AM

I'm glad I found this (very-very) old post concerning in-flight issues with an OS Max-s 35. I have my first one, a Max-s 30, (totally stock CL engine) on a SIG Banshee and am experiencing the same type of issues. Fox 35 burp type of issue when going inverted, and engine wants to quit on the second loop of an outside.

The original author said he went down to 22% oil on his engine and the in-flight problems went away. So, it sure does sound like the high oil content was the root cause.

I have been running 10% nitro and 28% total oil (50/50) on my Max-s 30 engine. The OS owner's manual for the Max-s 30 I found actually recommends 25% oil. I'll try the lower 25% oil and see how the engine does in the air.

I had similar issues wih a 35s back in the 80's. A frend recommended some changes. An Idle Bar Plug, a ST needle valve assembly and a smaller venturi. Fixed mine and it ran all the way up to 2022 when it was vaporized in a fire. Oh, we ran 22% oil.

Ken

Engine set up tips / Re: O.S. Max-s 35 wants to shut off?

« Last post by Colin McRae on Yesterday at 09:51:36 AM »

Quote from: Dave_Trible on Yesterday at 08:32:25 AM

I am running the 35S in a classic airplane at present. It can act like yours at times but getting the right plug (listen to what Denny Adamisin has to say above-they ran them for years) and maybe trying a little lower oil content but not below 22-23% should help. (mostly or entirely castor) One thing-it sounds like you are trying to run the old school long stroke engine sort of like a schnerle screamer. You will burn it up that way in short order. Run a 10-5 or 10-6 prop and cut that launch RPM down to a slower 2-4 break and go from there.

Dave

I'll go back over Denny's plug recommendations. I have been running a Fireball long-hot plug, but with one washer. I can try 2 washers as an additional test. Also, can try an idle bar type plug.

I may or may not have taken some life out of the engine the way I have tried to run it, which is somewhat like I run my OS LA engines. But the engine still starts easily and has good power. Hopefully have not taken too much life out of the engine since I was using a bunch oil at 28%. I'll also try increasing the prop pitch and richen a bit closer to a 4-2-4 break.

I have 2 more never-ran OS Max-s 30's that I got for a song. I'll use this current engine on my Banshee for my continued experimentation process to hopefully get it dialed in for stunt. Big picture, the Max 30 engine power output seems very good for my Banshee.

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