Taurus - Model Aeroplane News

[Dean Hunter]

I am going to build the "Taurus" an Ed Kazmirsky. A 70' 1970's pattern ship. Two things of interest (i) a phenolic trim bar (ii) L.E. scabs. I have Googled the first, its the second thats has me confused!! They are located under the leading edge top wing sheeting. Its possible that they are inserts that join two sheets? Tho why not a single sheet? Any thoughts appreciated ......

[kc]

That's a rather large model ! I suggest a 1/12 scale version at 70" might be more economical but if your workshop is big enough for 70 foot........

Seriously, I can see what you mean about the 'scabs' on the plan - they look like sheet joining tabs to me. Tabs underneath to reinforce. No cyano to join sheets in 1963. Nothing in the instructions to explain , but instructions on rolling the sheet suggest it needs very wide sheet.

SLEC used to sell sheet wider than 4 inches.

Phenolic trim bar would appear to be an ancient  ( pre modern radio with trims ) way to trim model.

Edited By kc on 08/09/2019 19:50:34

[Dean Hunter]

Agreed 70' span is a bit big, I will consider scaling it down to 70"

The trim bar looks a bit 'Heath Robinson' but seemed to work - providing the model survived the maiden flight?

I think the scabs are for joining sheets pre cyano........ I think sheet as wide as 6" is available from SLEC?

It should keep me busy over the winter months?

Thanks

[mal brewer]

The trim bar was used on 'reed' ( non-proportional ) rc. It was used normally on elevator, where control was split between two servos,one non self centering (the trim servo),and one self-centering servo,( the actuating servo ).The elevator pushrod lay about 3/4 along the trim bar,with the actuating servo giving most movement,and the trim servo providing ……er……... trim...…………….Mal

[Peter Jenkins]

There was a guy in the US who was making kits for the Taurus, which he called the Tauros as he'd updated the structure to a more modern style. I was lucky to get the last of the 50 he produced before he stopped. It's been sitting patiently in my workshop to be built for the last couple of years. I also managed to buy a Veco 45 on Ebay and when it arrived sent it down to Westons for them to make a silencer for it. They reckon that the state of the cylinder meant that it had not been fully run in - amazing. So, I shall have an interesting time putting that together when I can find the time. Are you going to do a build blog for this Taurus build?

[Michael Denest]

The trim bar Mal referred to was used in conjunction with a reed radio and provided extra movement for spins and inverted flight. Not necessary for our radios today. The "scabs" provide extra glue surface for the leading edge skins. It was Kazmirski's way of saving weight. They were provided already formed in the Top Flite kit. Eddie Taylor of Lazer Works modified the leading edge somewhat with a stringer that makes it easier to sheet.

Here's an interesting read on the original Taurus from the Model Airplane News construction article in RC Universe. Taurus

Kazmirski was a meticulous builder, the all up weight of the original covered airframe with engine, less radio was around 3 lbs. Back then, weight was a very big factor when pulling vertical maneuvers with a heavy radio and mediocre .45 engine. The airframe had to be as light as possible. Enjoy the build, it's a great flyer.

FMI: VRCS

Edited By Michael Denest on 09/09/2019 00:24:25

[Michael Denest]

Here are photos of my Taurus from the Top Flite kit; built sometime around 1966, finally finished and flown in 2010 with a grand total of six flights since completion. Silk and dope covering in the original Kazmirski scheme with a Veco .61 and Kraft single stick 72 MHz radio.

FMI: VRCS

Edited By Michael Denest on 09/09/2019 00:40:35

[Peter Jenkins]

Very nice Michael. I will have to keep an eye on weight as I build as I'm going to be using a Veco 45 to power mine.

[Michael Denest]

Thanks Peter. The nice thing about the Veco .45 and the .61 is they fit the same mounting holes.

[Michael Denest]

Posted by Peter Jenkins on 08/09/2019 23:57:54:

I also managed to buy a Veco 45 on Ebay and when it arrived sent it down to Westons for them to make a silencer for it. They reckon that the state of the cylinder meant that it had not been fully run in - amazing.

The Veco .45 can be a bear to run in (there's no ring). The best thing to do is to use a fuel with extra castor oil. These older engines were not designed to use synthetic oils but mixing castor in will work ok. Don't waste time on the bench trying to run it in, install it and fly, leaving the settings for a slightly rich condition.

Can you provide details on the muffler they fabricated for you? 

The photo below shows the original Taurus and final version as found in the Ed Kazmirski estate.  His last two designs were the Simla and the pusher Taurus. 

 

Edited By Michael Denest on 09/09/2019 01:18:34

Edited By Michael Denest on 09/09/2019 01:22:45

[Peter Christy]

Posted by Michael Denest on 09/09/2019 01:16:19:

The Veco .45 can be a bear to run in (there's no ring). The best thing to do is to use a fuel with extra castor oil. These older engines were not designed to use synthetic oils but mixing castor in will work ok.

I have to disagree! Castor fuel belongs in a museum, not an engine! I'm running quite a few 60s era engines (including OS MAX 40H, pre-Blackhead Webra 61, and several HB25s - same internally as the Vecos of that era) and all run perfectly happily on a good synthetic oil.

I bought the Webra in 1968, and it is still hauling a Dave Platt Kingpin (very similar to a Taurus) around in grand style today. The only recommendation I would make is to use a good quality helicopter fuel (I use Model Technics Bekra fuel) as this is intended for applications where cooling is restricted.

Although cooling is not restricted in a Taurus, these old engines can run a bit hotter than modern ones!

Also, most old engines use long reach plugs. Although they will run on short reach plugs, it does remove the element from where it really needs to be, and reduces the compression slightly. 4-stroke plugs are generally long reach types, and work really well in older engines.

BTW, one trick to forming the "wrap-around" leading edge on a Taurus is to wet ONE side of the LE sheet with water. This will make the wood curl up, and make it much easier to glue in place without splitting the sheeting!

Nice project BTW! My Kingpin turned out about 2lbs lighter than the design weight, not because I'm a light builder (I'm not!), but because modern radio gear is MUCH lighter than that for which the model was designed!

--

Pete

[kc]

Would it be considered sacrilege, in such a classic design, to suggest changing the LE construction to one using a false LE with separate upper and lower wing skins lapped over it with a front capping piece? To me that would be easier than trying to bend balsa right around the LE.

The original plan and article is on Outerzone if anybody needs it.

Edited By kc on 09/09/2019 10:47:21

[Peter Christy]

Posted by kc on 09/09/2019 10:44:07:

Would it be considered sacrilege, in such a classic design, to suggest changing the LE construction to one using a false LE with separate upper and lower wing skins lapped over it with a front capping piece? To me that would be easier than trying to bend balsa right around the LE.

Not by me, it wouldn't!

The "KingPin" appears to be Dave Platt's variation of a "Taurus" (many of the designs of that era were Taurus clones!) and uses the construction you suggest - plus a fully sheeted wing.

Looks like a Taurus and flies like a Taurus! The only difficulty I found was in accurately joining the two wings without the benefit of dihedral braces / doublers.

--

Pete

[Brian Cooper]

Wow, a Taurus. . . I had one of those back in the 1960s when I was about 11 or 12.

My one was powered with a fairly limp-waisted Merco 49, and equipped with RCS 10 channel reeds radio.

As I recall, it was a very nice aeroplane to fly. . . Peter Christy has been around long enough to (probably) remember it.

B.C.

Edited By Brian Cooper on 09/09/2019 12:27:23

[Peter Christy]

I believe I do remember it, Brian! When I first moved from Devon to the Watford area, around 1974, I had a Taurus clone. It was called a Tornado and had been produced by a Devon kit maker, but was really a Taurus with a foam wing!

I modified mine to conventional ailerons (never liked strip ailerons!) which was very easy with foam wings. And it was powered by that same Webra as is now in the KingPin!

I eventually retired it when I replaced it with a Gangster 63 (also powered by that same Webra!), and John Sharman bought it off me. I've no idea what happened to it after that....

--

Pete