Author Topic: Wing area range for OS Max S .35? (Read 2772 times)

Joe Ed Pederson · « **on:** February 22, 2018, 07:43:44 PM »

I have a couple of OS Max S .35s from the 1960-1970s. What is a good range of wing area and/or flying weights for this old engine?

Also, a friend gave me his old Carl Goldberg Cosmic Wind. Are the old Goldberg Shoestring/Cosmic Wind planes capable of the full pattern? I haven't flown since my 20's, but back then I had worked up to a Carl Goldberg Shoestring and managed inverted, wing overs, and loops. I'm building an old Top Flite Tutor kit (45" span, 410 square inches) I bought at a hobby shop between 1978 and 1983. The sticker on the box says, "Hobby Town, Lincoln, NE $24.95." I'm going to try and work up the courage to learn the entire pattern with the help of the Lafayette Escadrille in St. Louis (80 miles from where I live).
Joe

Dave_Trible · « **Reply #1 on:** February 22, 2018, 08:17:16 PM »

That Goldberg Cosmic Wind is a very nice, fun flying airplane but not really a pattern airplane. It does all the round maneuvers very well but isn't intended to do squares etc. A great airplane if you still need to learn the basic round stuff though. Your Tutor will be better for learning pattern stuff. Your OS should pull that well. As far as wing area for the OS S its in the same category as the Fox .35-perhaps with just a little more power and smoothness. That means something like Nobler size or about 550 squares is about the practical limit for good performance. It will work well in most all the older .35 size classic designs.

Dave

Dan McEntee · « **Reply #2 on:** February 22, 2018, 08:19:00 PM »

Hi Joe!
Good to see you posting. The OS.35s will work well in the Goldberg models, and they can fly the whole pattern. A renovated model will do to get your chops back and some time under your belt. The OS.35s will also work well in that Tutor. It's on the small side and some use the LA.25 in these today, so the .35 will have plenty of punch. The typical .35 size models like Twister, Banshee, the Brodak line of profiles, all should be within range. For a full fuselage model, a Jetco Dolphin will fill the bill.Staying the the 500 to 550 square inch range should keep things lively. Our Ice-O-Lated contest is this Sunday, come on up if you can. Otherwise when we do some Saturday flying we'll keep you in the loop email wise. We'll try to make it worth the 80 mile drive!
Type at you later,
Dan McEntee

Joe Ed Pederson · « **Reply #3 on:** February 22, 2018, 08:25:39 PM »

My thanks to Dave and Dan. Dan, I hope to come up for the Ice O Lated, but I can only come on Saturday.
Joe

Rick Bollinger · « **Reply #4 on:** February 22, 2018, 08:30:42 PM »

Joe where do you live? I am about 3hrs North of ST Louis.

Dane Martin · « **Reply #5 on:** February 22, 2018, 08:32:12 PM »

Here's John Wright putting up a killer flight with a Tudor and an os 35.

Brent Williams · « **Reply #6 on:** February 22, 2018, 09:07:41 PM »

Here's Gordan Delaney's Warburton Tony that he built in late 1970.
I can confirm that when I flew it last summer, that it performs nicely using a stock OS 35-S and a Rev-Up 10x6.
560 squares or so.

Dan McEntee · « **Reply #7 on:** February 22, 2018, 09:13:38 PM »

Quote from: Joe Ed Pederson on February 22, 2018, 08:25:39 PM

My thanks to Dave and Dan. Dan, I hope to come up for the Ice O Lated, but I can only come on Saturday.
Joe

The contest is Sunday only. The only thing that maybe on the circles Saturday is ducks! Supposed to be yucky weather until late Saturday night and clearing for Sunday. Not sure of wind yet. Keep us posted on model developments and when you get something ready to fly we'll get together as soon as the weather starts to stay better.
Type at you later,
Dan McEntee

Joe Ed Pederson · « **Reply #8 on:** February 22, 2018, 09:47:44 PM »

To Rick,

I live in Cuba, MO on I-44 about 80 miles southwest of St. Louis.

Joe

RandySmith · « **Reply #9 on:** February 22, 2018, 11:43:23 PM »

Quote from: Joe Ed Pederson on February 22, 2018, 07:43:44 PM

I have a couple of OS Max S .35s from the 1960-1970s. What is a good range of wing area and/or flying weights for this old engine?

Also, a friend gave me his old Carl Goldberg Cosmic Wind. Are the old Goldberg Shoestring/Cosmic Wind planes capable of the full pattern? I haven't flown since my 20's, but back then I had worked up to a Carl Goldberg Shoestring and managed inverted, wing overs, and loops. I'm building an old Top Flite Tutor kit (45" span, 410 square inches) I bought at a hobby shop between 1978 and 1983. The sticker on the box says, "Hobby Town, Lincoln, NE $24.95." I'm going to try and work up the courage to learn the entire pattern with the help of the Lafayette Escadrille in St. Louis (80 miles from where I live).
Joe

That will fly a plane from a Ringmaster to a Stiletto, and 25 to 50 ounces

Randy

Joe Ed Pederson · « **Reply #10 on:** February 23, 2018, 07:37:34 AM »

Thanks Randy.

Joe

Ken Culbertson · « **Reply #11 on:** February 23, 2018, 04:23:13 PM »

Love that engine. I still have the one I competed with in the late 70's. It sat on the shelf for 30 years and started for the 1st time on the 2nd flip last weekend. It powered a ship that was around 580sq but very light. I built a larger version at around 610 and 45 oz and it was not enough power.
Treat them right and they last forever.

Ken

Trostle · « **Reply #12 on:** February 23, 2018, 05:37:18 PM »

Quote from: RandySmith on February 22, 2018, 11:43:23 PM

That will fly a plane from a Ringmaster to a Stiletto, and 25 to 50 ounces

Randy

Randy's advice is great and is based on his wide experience with stunt model power plants. It will work fine on the smaller "sport models" similar to the Goldberg Shoestring. I would suggest that if the goal is to mount the OS 35S on a full stunt ship, then look for a design that is between 550 and something less than 600 sq. in. with the weight around 45 oz.

I am aware of one OS 35S that was mounted on a semiscale model that won the Walker Cup in 1970. The airplane had about 610 sq in and weighed 47 oz. It used the standard OS JetStream muffler for that engine without the inserts on the internal baffle and the outlet. I think this is the only time the OS 35S was used to win the Nats/Walker Cup. And the second time a muffler was used to win that distinction. That airplane would not be competitive now against the current flock of top pilots/planes. Also, that model was not in the same class as the Super Semi-Scale Stunt Ships (S⁵) developed and influenced by Al Rabe that started to appear at that time.

The only issue I know of with these engines is that the connecting rod has a limited life (maybe less than 500 flights). Connecting rods with bushings have been available from time to time.

Keith

Randy Cuberly · « **Reply #13 on:** February 23, 2018, 07:25:02 PM »

The 35s is a fine Engine, significantly better than a Fox 35. There are some floating around that have had ST35 bushed rods installed and even a few that have after market ABC Piston Sleeve Assemblies. If you can find one of these (they typically go for a premium price), they are truly a terrific light weight engine that will last a good long time.

The 35S is a good choice for a Gieseke Nobler! And could still be competitive in Classic in the right hands!

Incidentally Bob Whitely used two of these engines in a Twin called the "LA Heat" to place fairly high at the Nationals. The only Twin to ever do so! Being reliable enough to achieve someting like that times two is a significant feat for any engine!

Duhhhh....

A good friend has just reminded me that my very OLD and feeble memory is still faulty as ever!
I admit I had completely forgotten that Windy Urtnowsky also campaigned several Twins at the Nationals and made very fine showings with them.

Bob Whitely's excellent flying LA Heat was somewhat earlier and I believe probably the first Twin to make a good showing at the Nationals. If memory serves me correctly Bob's finish was also the highest ever with a Twin at only One point out of the top Five. I guess that's why it stands out for me! Also I saw it fly and did not have the opportunity to actually see the others!

At any rate any such accomplishments with Twins is truly noteworthy but for me the one with the little OS35's singing in unison was a thriller.

Another Twin worthy of note of course was Gordon Delaney's Too Much. Especially in the hands of the incomparable Bart Klapinsky during exhibition flight at various contests. Unmuffled Foxes singing and corners not to be believed with a giant airplane.

My apologies for an old and faulty memory!

I love twins!

Randy Cuberly

Matthew Brown · « **Reply #14 on:** February 24, 2018, 04:33:22 PM »

Since this was brought up, I have an old 35S I picked up at a swap meet a couple years ago. I flew it a bit earlier this past season and decided it was a bit too worn out to run well.
Are there parts available to bring it up to spec? I hate to dump it but also don’t feel the need to pump a big bunch of money into it either.

Matt

Dennis Moritz · « **Reply #15 on:** February 24, 2018, 10:15:03 PM »

OS35s is down on power compared to the FP, LA engines and the like. When used within power range, able to 4 stroke/2 stroke they are sweet and docile when run hard in constant 2 stroke they feel strained. I had 2 models powered by the 35s that were better served by more powerful engines. Both weighed over 45 ounces. One a Prowler, one an Oriental. IÂ’d use the 35s on the Goldberg profiles, Ringmasters and light weight profile stunters, around 35 ounces.

Sent from my iPad using Tapatalk

Randy Cuberly · « **Reply #16 on:** February 24, 2018, 10:32:43 PM »

As I mentioned earlier, there are OS35S engines and there are OS 35S + engines running around that have bushed rods and ABC Piston Sleeve assemblies from Brian Gardner that are Quite another story. There is currently about 75 to 100 such engines in circulation and if you look hard you can probably find one! Personally I would take one of these over any FP40 ever put together by anyone! In fact I have taken several of them!

Randy Cuberly

Brett Buck · « **Reply #17 on:** February 25, 2018, 12:48:13 AM »

While I would certainly note the fact that people used to fly fairly good-sized airplanes with the OS-35s back in the day, now, I would definitely only consider the low end of the old range, maybe 450-500 square inches at the very most, and with as much weight saving as you can manage. You are in a real uphill climb up against AeroTigers, PA40UL, Magnum 36s, and even 25LAs.

A stock engine is not any stronger than a Fox, and it's substantially less durable - meaning if you try to improve the performance with Vitamin N, you are going pound out the connecting rod in 200 flights instead of Keith's 500. I vaguely recall that there was another engine from another manufacturer with a connecting rod that fits the 35S and is very durable - I want to say an STC35 - but for goodness sake don't stake any money on it. RPM used to make a replacement, as well.

Note that most of the good results back in the good old days were with the Big Art 35S, not a stocker.

To be honest with you, all things considered, I think I would rather have a Fox than a stock 35s - same or better power stock, same fuel requirements, greater tolerance for nitro, and much more durable. The only advantages for the 35S are the fit and finish, and being able to change venturis easily. Not that you should toss them out, just be aware of the limitations and don't expect miracles.

Brett

FLOYD CARTER · « **Reply #18 on:** February 25, 2018, 10:56:37 AM »

The two OS35S engines that I used both had steel cylinders. This required fuel with 25% oil, as used in the Fox 35.

I didn't keep these engines, but I have a coupleof after-market bushed connecting rods that I never needed for these engines.

Skip Chernoff · « **Reply #19 on:** February 25, 2018, 12:45:17 PM »

I've got a Max 35s in my OTS Phase II plane, an original Polywog Chief. It's light at 33 oz and flies beautifully with that old OS Max s. I use a 10x6 prop, 60' lines center to center. We've done very well with it the last few years at Brodaks. It's wonderful in still air,doesn't like the wind so much......PhillySkip

Author Topic: Wing area range for OS Max S .35? (Read 2772 times)

Matthew Brown