History of Senior Telemaster
 

I though some of you may find this interesting. So I contacted Jim Martin and worked with him on this bit of history.
Hope that I am not posting it out of place.

History of the Telemaster

The Telemaster was designed by Karl-Heinz Denzin while he, Denzin, was employed by Alexander Engel KG of Knittlingen, Germany. Older free flight modelers will recognize one of the design features which is the lifting stabilizer. Because of the lifting stabilizer, the usual balance point of "one-third of the wing chord aft of the leading edge" did not apply to Telemasters and modelers put the balance point anywhere from 40% of the chord to 50%.

At the time that I introduced the Telemaster into the USA market (I'm guessing the late 1960's or early 70's) the digital proportional radio hadn't been invented and the usual control system was the reed system. Reeds required an airplane that flew itself a bit more than the later digital proportional required, so the lifting stabilizer was a pretty good match to the reed systems as the stab lifted a bit more when airspeed increased which caused the nose to drop somewhat and a more level flight path to be attained. This inherent stability also made (and still makes) the Telemaster a good trainer for beginning RCers.

The first Telemaster kits that were imported from Alexander Engel had conventional "D tube" leading edge wing sheeting. Sometime in the 70's (and the dates are hard for me to remember) there was a bad shortage of balsa wood which was caused by the building of huge tanker ships for liquified natural gas. At this time Alex Engel substituted Duracell sheeting for the balsa D tube cover. The Duracell was awful. We had a lot of complaints because the plastic sort of a hard foam cracked and broke when it was bent. So, future large Telemasters started to use wood stringers along the top surfaces of the leading edge. It seemed that these sub spars apparently produced a more even airflow over the wing and probably turned out to be an aerodynamic improvement.

Telemaster was a German design and the original Telemaster kits were manufactured in Germany, but the name "Telemaster" has no German roots whatsoever. Tele comes from the Greek and Master is an English language word. The airplane could have been called Telemeister, which would have been Greek and German, but it wasn't, and the reason is that Alex Engel was a huge admirer of the United States of America. Alex had been a German soldier, a radar operator during WW2, and he was the operator who detected the huge Allied invasion of Sicily. Alex was captured by the Americans and ended up in a US POW camp in Nebraska where he got an English language dictionary. He studied English and became an interpreter for the US government. But he wanted to go home to Germany after the war and he returned to his home in Knittlingen which is a small town just north of Stuttgart.

An interesting thing about the Telemaster is that it was used to run “pull strings”, used as pilot leads to pull guy wires and electric wire over mountain ranges and other natural barriers in Europe. As of late the Telemaster has also become a tool used by scientists to do different atmospheric sampling tasks and aerial surveying. Also the Telemaster has become a popular subject for testing of autonomous flight controls. So it is really amazing how a 50 year old well-designed model still is so popular and to this day is venerated as a great design and keeps being used in new roles.

Jim Martin
Former owner of Hobby Lobby

Posted by Jay Burkart

RE: History of Senior Telemaster
 

Fascinating!

RE: History of Senior Telemaster
 

Very interesting Jay. Thanks for posting this. Right forum for it I reckon.

RE: History of Senior Telemaster
 

I read on a German website yesterday that Karl-Heinz Denzin died in December of last year. I believe he was 87 years of age.

RE: History of Senior Telemaster
 

I am a little confused by the above statement.

Digital proportional was developed in the early 60's by Doug Spreng. Ed Thompson designed the Digitrio around 1963/64 as I built one in 1965 from the articles in RCM with kits from World Engines (Controlaire). Several digitial radios were available from the mid 60's, F&M, Bonner, Orbit, Micro Avionics etc.
Reed radios from about 1958 disapeared as well as analog proportional from Space Control and Orbit from the early 60's. The late 60's and early 70's was mostly all digitial with only used reeds available.

RE: History of Senior Telemaster
 

Thanks for that information. Guess we should have edited it from not being invented to not being
popular yet.
They were expensive back then, thus the reason for the Digitrio kits.
I was flying reeds then still and I live in Cincinnati the home of Controlaire but I still could
not afford even the kits.
Thanks,
Jay

RE: History of Senior Telemaster
 

I started R/C with my Dad in 1969 (Heathkit GD-19, Falcon 56 and ST G.23R/C) and it was rare to very rare to see any reeds at the flying field. I think the digitial Proportional revolution was well underway by the late 1960s.
I remember going to fields in the early to mid 1960s and all we saw were reeds or single channel gear.

RE: History of Senior Telemaster
 

With all respects to Jim Martin's memory, I was working from 1976 to 1979 as sales manager at Hobby Lobby. I was in Germany with Jim Martin the evening over dinner when Alex Engel told Jim that he was not making the Telemaster kits any more and gave Jim the rights to it.
We got Joe Bridi ti do the kit for us and for some reason, Joe decided to put strips along the wing rather than sheeting...also Joe loved strip ailerons and the USA version of the Telemaster had strips versus the German aversion which had barn door ailerons. I have had both and the barn door ailerons worked far better than Bridi's version. I still have one of the German Senior Telemaster kits in my "stash".
The German version of the Telemaster used very stout dihedral braces and the Bridi USA version used strips of light ply for the dihedral braces...and I remember well that we were getting daily complaints that the wings were folding up, so Bridi added a bit more dihedral bracing.
Oh, the "real" telemaster can fly with three channel or four..rudder is quite effective.
Regards to all,
Frank Schwartz

RE: History of Senior Telemaster
 

I'll second that Frank. I once flew my STM twice in a strong wind without the ailerons even being connected! I thought all of that wallowing about was caused by the wind! It flew better once I'd connected the ailerons mind!:eek:

RE: History of Senior Telemaster
 

Wonderful thread gentlemen and Jay thank you so much for your posts. Have long been a fan of the Tellys but never really knew any of the history, Fasinating[8D]

Here is my current Telly:


John

RE: History of Senior Telemaster
 

Frank,

In your recollection, what year was the first Telemaster flown in the states. If it is before Jan 1, 1976, it qualifies for the VRCS.

RE: History of Senior Telemaster
 

Well, here's an ad for the kit from the December 1975 issue of RCM so I guess that makes it VR/CS legal - just ;)

In fact the plan/construction article was featured in the October 1975 issue.

Ray

RE: History of Senior Telemaster
 

Definitely qualify....
I went to work at H/L in 1976 and the plane (the German kit) was on the shelf then. Also the standard Telemaster , that is the 6 foot version...and also from Alex Englel, The Rot Adler, which was a neat Biplane ca which translated meant the Red Eagle.
Yes, the Sr. Telemaster and the standard Telemaster were both sold and stocked by Hobby Lobby before 1976. Another plane stocked before 1976 was a neat 40 size F5 styled plane from TruLine in England and the plane was designed by the late Dave Boddington called the TruLine Tiger...and I built a couple and flew them as well and have a kit in my "stash" All gone, but not totally forgotten.
Hence my theory of life #2 (Murphy's law is #1) and that is "Everything good gets discontinued"|.

RE: History of Senior Telemaster
 

Didn't know that it was a Boddington design.

Ray

RE: History of Senior Telemaster
 

[link=http://www.rcmplans.com/issues/requested/content/reviews/pdf/r-rv-telemaster-041973-1-1.pdf]April 1973 RCM original STM article[/link]
October 1975 RCM presented the Bridi STM with plan (not freely available)
Original design must have been 1967/68.

RE: History of Senior Telemaster
 

Dave Bodding designed the TruLine Tiger. Yes, it has his name on the plans...and is a fantastic sport flyer with no bad characteristics. Interesting airfoil. The thickness tapers to the end but the leading edge and trailing edge stays the same...in other words..the root rib is not the same as the tip ribs....
I must build another....the last one did a figure nine when the elevator servo went bad in a low level loop. Isn't always that way?
Incidentally, the wing is foam and is covered in obechi thin sheet. Fuselage is basically a box that requires a bit of carving to round, and the tail feathers are 1/4 sheet. Mine performed very well with a stock K&B40. Often thought of blowing it up to 60 size so there would be enough rrom for retracts. Also that picture in the ad is my first one that I built.

RE: History of Senior Telemaster
 

This is amazing history I would like to ask if I can put in our Clubs newsletter? Me and my 11 year old son both have senior telemasters and they fly great . I love this plane.

Thanks for the history to all.


Steve


Chicagoland Radio Control Modelers

RE: History of Senior Telemaster
 

I found the attached some time ago. I think you might all be interested.

RE: History of Senior Telemaster
 

-Interesting read, thanks! Was the purpose of the lifting stab to allow for a wider CG range for payloads, or to minimize trim changes with airspeed variations, or both?
-A bit of trivia, I noticed my early '90s Sr Tele kit says "Another Great Planes Kit". Did Great Planes make Sr Telemaster kits back then?

RE: History of Senior Telemaster
 

Was the purpose of the lifting stab to allow for a wider CG range for payloads, or to minimize trim changes with airspeed variations, or both?
-A bit of trivia, I noticed my early '90s Sr Tele kit says ''Another Great Planes Kit''. Did Great Planes make Sr Telemaster kits back then?


Quite a lot of the old free flight designs had lifting tailplanes. I believe Denzin was just following a practice which had been successful with his earlier designs.

I don't know whether Great Planes ever made the Telemaster but Precedent made them under licence in the UK. Have you ever compared the T240's flying surfaces to those of the Senior Telemaster? Aerotech also sold Telemasters in the UK back in the 1990s but I don't know whether they cut the kits themselves or imported them from America.

RE: History of Senior Telemaster
 

The Precedent T240 had the wings and tail of a Telemaster

RE: History of Senior Telemaster
 

Wow, I can't believe I never saw this thread until today...
I have two of the STM, one I currently fly and another w/ wings about 60% completed...if I only had more time...
Thank you to all of the posters that have shed some light on one of my favorite planes.
Bob

RE: History of Senior Telemaster
 

The current version of this article is [link=http://time.fh-augsburg.de/cgi-bin/dl.pl?id=Telemaster.pdf]here[/link].

As to the lifting stab, I would agree that Denzin was following older practice, but there might be yet another, practical reason: The flat-bottom stab is easiest to mount with the correct incidence, even if the whole tail group would be only strapped on with rubber bands (what was common practice still in the sixties).

And the cambered stab airfoil is good IF the model is flown in a flight regime where the stab really lifts, which means with a far rear C/G. Only in this case, the stab doesn't additionally load the wing but unburdens it, what makes for less overall induced drag. This way, the model can haul even more load, for what it was designed in the first place (providing this aerodynamic layout and a sturdy wing).

RE: History of Senior Telemaster
 

Thanks Ustik, that's the answer I was looking for. I heard that the aft CG was for a reason, but I didn't think about induced drag.

RE: History of Senior Telemaster
 

<div style="margin: 0in 0in 10pt"><span style="line-height: 115%; font-size: 10pt">My father (now 72) built a Senior Telemaster some 30-35odd years ago. I guess you can say he introduced the plane to my country (Malaysia). However he built the plane by plan only, not by kit. Because of the size, we carried it around in a Volvo Station Wagon. It was and still is a beautiful slow flier, a style of flying which is rare here nowadays (builders are rare this part of the world).</span></div><div style="margin: 0in 0in 10pt"><span style="line-height: 115%; font-size: 10pt">I think it would interest you to know as I have not read of anyone doing so, that my father scaled the plans for the plane down by half and built &frac12; scaled down version as a trainer. My brother who took over building, built a &frac14; scale 3 channel (no rudder) version and all few beautifully. I was woundering if anyone else have scaled down the plane, or even scaled up?
</span></div>