Trivial Pursuit - Special Edition

[Ian Hewitt]

Hi Stunthangar,

Just looking for some advice having purchased a Hobby Fasteners Trivial Pursuit: Special Edition from a friend yesterday together with a Tom Lay ST 60.

Having glanced at the plans - beautifully drawn by Pat Johnson, I am starting to think that this model may need a piped 60 to haul it around..  ..as it says on the box..

Would an unpiped ST60 be up to the job?

The other issue is that I may need a new car to carry the completed model..  ..but that is not such a pressing matter at this stage.

Thanks in advance

Ian

[M Spencer]

They used to say ' If it dosnt fly , put a Supre Tigre 60 in it .
Ted might have somthing to say about that .



to illustrate the subject . Tank Volume should be o.k. . But S Tigre 60 can shake , nose length / C.G. might come into it .
One can get to pedantic ( who , me ? )  Theres S T 60s & ST 60s. A good one on a three blade should cope . Not being a pipe man , myself .

Stand by for howls of derission . You should do it electric .      2 Kilo / 72 Oz. probly a comfortable weight before it'd feel the strain .
Of Couse . Theyll all tell you , you need a pipe for the wind . But if your not aiming for No 1 at the World Champs , it might not be neccesary .



Get out a crayon & see if the engine fits , with 7 ounces of juice . 60 Oz & it'd fly like a dream . A unpiped SF OS 46  is much a match for the S Tigre 60 .
I believe som,e may say a LA 46'd do it .  LA Maybe , 21 46 Yes . But the word ' authoritively ' might be of some use . Ipso Facto .          Stand Clear .
Explosive Replys anticipated .

[Steve Helmick]

No problem at all for the ST .60bb, but the plans were drawn by Pat JohnsTon, not that Johnson fella.  Steve

[Brett Buck]

Hi Stunthangar,

Just looking for some advice having purchased a Hobby Fasteners Trivial Pursuit: Special Edition from a friend yesterday together with a Tom Lay ST 60.

Having glanced at the plans - beautifully drawn by Pat Johnson, I am starting to think that this model may need a piped 60 to haul it around..  ..as it says on the box..

Would an unpiped ST60 be up to the job?

   It will fly the airplane- it's not that large.But it would be a real shame to give up on the performance on such a good airplane. I also suspect you will have less-than-ideal pitch response unless you make some changes. Even with the RO-Jett 61, it needed slightly more flap than elevator (as discovered on the second-to-last flight) , with an ST60 it might have to have a lot more flap than elevator   

    It was not designed to fly with ancient 4-2 break engines from the 80's and it certainly is not optimized for that style of flying. It is not a matter of "enough power", it is a matter of "right kind of power"

     Brett

[Ian Hewitt]

Thanks for the responses.

I appreciate that this is a finely tuned design and really needs a strong power delivery in order to operate to the full - as Brett makes clear.

I was talking with one of our leading flyers at the CLAPA Champs this weekend - he said that the US designs are really designed for US conditions which derive from a big continental land mass - thinner air and less wind. By contrast our home conditions include air with the consistency of pea soup.. ..and strong winds/turbulence. As a result we don't really need the very thick wing sections to generate lift.

I was wondering if I were to 'butcher' the wing section by slimming down the profile by 1/8th each side whether I might lower the need for engine power and better adapt to the thicker air (and often wet/turbulent) that we experience on this side of the pond. With apologies to the purists, I wonder whether this might be worth a try - or maybe I should leave well alone and move the kit on to someone better able to use it?

I don't expect to start cutting wood anytime soon and can find another home for the Tom Lay ST 60 - having been sold a Taurus part-kit by the same guy on Sunday - big vintage design with a huge wing but very thin section.

Thanks again

Ian

[roy cherry]

hi ian please dont cut the wing down on yor trivial you will have more than enough power to pull the plane i am my self flying a trivial at present  if you want to talk  just call me any time roy cherry   

[Brett Buck]

Thanks for the responses.

I appreciate that this is a finely tuned design and really needs a strong power delivery in order to operate to the full - as Brett makes clear.

I was talking with one of our leading flyers at the CLAPA Champs this weekend - he said that the US designs are really designed for US conditions which derive from a big continental land mass - thinner air and less wind. By contrast our home conditions include air with the consistency of pea soup.. ..and strong winds/turbulence. As a result we don't really need the very thick wing sections to generate lift.

I was wondering if I were to 'butcher' the wing section by slimming down the profile by 1/8th each side whether I might lower the need for engine power and better adapt to the thicker air (and often wet/turbulent) that we experience on this side of the pond. With apologies to the purists, I wonder whether this might be worth a try - or maybe I should leave well alone and move the kit on to someone better able to use it?

    It doesn't need "strong power delivery" to operate. It might be the best ST60 airplane ever, probably a close call for either this or a Bad News. My point was that no matter what airplane you fly, you would be giving up tremendous performance, and particularly so for this airplane, compared to how it might fly with a regular engine.

   I would also disagree with your "leading flier", if you are using 4-2 break engine, you really have no idea how good wind performance can be. Wind and turbulence is why ST60s and the like haven't been used for years. In the brief life of the Great Expectations, it flew very competitively in winds that caused at least one world champion to crash, and it's very similar predecessors flew in winds you couldn't stand up in.

    My point on the topic of flaps was about the fact that they were small for even a tuned pipe airplane and an ST60 airplane will ideally fly with more flap than a tuned pipe airplane and lots more than electric. This is because the speed will fall much more in the corners with an ST60. That also suggests "thinning out the airfoil" would likely be a bad idea - both from a speed control perspective and a cornering perspective. An ST60 has plenty of power but poor speed control, so you want lots of parasitic drag to try to stabilize the speeds. Tuned pipe airplane have more or less infinite power, but aren't run anywhere near max power, but they control speed vastly better, so you can get away with smaller flaps.

    I am sure it would be a very nice ST60 airplane with appropriate trim changes . But it's still an ST60, and it's not 1985 any more.

   Just for reference, while Ted can certainly speak for himself very eloquently, I am his flying buddy and was his principle collaborator/experimenter/coach/tool box carrier for the design of this airplane and its (unfortunately brief) career and was in fact present and probably launching almost every flight it ever had. It was designed along the same principles we came up with at a Thanksgiving party in about 1990, where we came up with the ideas behind the Trivial Pursuit/Star Gazer and my own airplane, the Infinity.

      The Great Expectations was very close to the Trivial Pursuit as far as things like flaps and airfoils go, the one big difference was that it discarded the idea of flying with lots of rudder offset (which was cut out - with a saw - from the second Trivial Pursuit and the first Star Gazer, and deleted for the Great Expectation and Star Gazers 2-4). So I do have pretty extensive knowledge of how it flies.

    As mentioned, with the RO-Jett 61 BSE, and at the weight it was built (I want to say 64 ounces) it needed slightly more flap travel than elevator, as discovered after the WC and before NATs. In fact when it crashed, I was afraid that my suggested elevator horn adjustment to slow it down had slipped and cause the crash, meaing I was partly responsible for it. Turns out, not, but it was an uncomfortable few minutes.

    I certainly do not suggest drastic modifications and if the intent it to fly it with an ST60, you need all the airfoil you can get. I *would* suggest making the flaps removable (using a single hinge pin) to ba able to use larger chord flaps if the airplane either comes out heavy or has a 4-2 break engine.

     Brett

[M Spencer]

We assume Mr Hewitt isnt after a ' Top 15 ' in the World Champs .

Read the ' Thunder Gazer ' stuff ( again again again - One dosnt ' absorb ' all the minuate in one hit . )
Bretts Comment There on the Hi Drag Wing is exactly WHY the T. G. went to the Werwage T - Bolt Wing .

Thick wing and hi lift , gives a added capacity to avoid gravity , as in ' That was Close ' a inch is as good as a mile , etc .

Id think the WIDE Flaps with limited travel , or a exponential  , would help maintain corner speed .
IF Its a Tom Lay ST 60 , its gunna work . Did Win a World Champs or two , so cant be entirely hopeless .

Center Of Balance . Without the pipe back there , but heavier engine , id GUESS a 1/2 inch off the nose ( Spinner 1/2 rear of plan posn. )
might be something like right for the correct plan C.G.  . Or Finalise engine bolt posn after assembly .

Being a pommy back yard eng8ineer with a soldering iron ?? Two 1/16 th mild steel plates , drilled for Two Positions !
Maybe 1/2 seperation , and you could throw it 1/2 aft with a 1/2 prop extension . OR 3/4 if the bolt space is 19 mm .
AS IN Dual Pattern , 8 1/8 nuts . 4 ea side . The Spitfire  Has this for G 51 Pattern overlaid on ST V60 pattern .
The Metal over the bearers are about 3/8 x 2 in or suchlike . cleaned sanded threads oiled & epoxied on . 
Basic one is three per side , if its nose heavy , shift it back & cut off the extra nose length . Avoiding adding WEIGHTS .
for those into chain saws and disc grinders . As In the fittings fitted - rear bolt becomes front , theres a second the same far back already fitted . A 3/4 prop extn. shaft , could then go in ? 

Whatever , it isnt going to fly to bad . Live & Learn . try differant props . Some'll be much better . wood Ones generally should be thinned and refined to pitch & L E Radius . Even undercamberd .
Like a 60s Gorrie Mi - T prop !! These dont need nuthin . Send em all to me ! . 
To ME the important THING is that itll take FULL UP being slammed on , or down . Without making a hole in the ground . A Stall turn even ! , if the forces of nature try to get the better of you .

SO , a bit of Carbon Veil in the Tailplane Spar , and other bits . If your of a sufficently decadant disposition .

[Ian Hewitt]

Hi again,

Many thanks for the further replies - very helpful and insightful.

I think that I am starting to zero in on the issues.

I bought the kit from an Irish flyer who was visiting the UK to take part in the CLAPA Champs. He said that the Trivial Pursuit had been a favourite with a former Irish champion who had used an ST60.

I have got enough now to do some more thinking..  ..may be some time before it gets any further but thanks again for the pointers. I definitely will not be butchering the ribs or altering the aerodynamic set up and note that the flap/elevator may need to be biased towards the flaps.

Ian

[Dennis Toth]

Ian,
Just a thought but the ST60 was an RC engine designed to run in a 2 cycle. Now the mods the Tom Lay did kinda detuned for the 4-2 run style but it should still do the wet 2. Looking at the review for the ST60 (http://sceptreflight.com/Model%20Engine%20Tests/ST%2060%20RC%20%281966%29.html) the engine peaks out at around 11,500 rpm. To get there you will need to run a fuel with at least 25% total oil (50/50 should work) and keep the ring good. If you fly on 66' lines at a lap time of 5.4 you can likely get there with a 12x4.5 ish wide blade prop and fairly open muffler. If you run the 2 - 2+ -2 kind of run you could be very close to the more constant speed the ship likes. If you can get one of the Brain Gardner ABC setup it will definitely do this and more.

The ST60's were also run on pipe (Windy U) and it seemed to do just fine just watch the % oil and don't overload it.

Best,    DennisT

[Dan McEntee]

Ian,
Just a thought but the ST60 was an RC engine designed to run in a 2 cycle. Now the mods the Tom Lay did kinda detuned for the 4-2 run style but it should still do the wet 2. Looking at the review for the ST60 (http://sceptreflight.com/Model%20Engine%20Tests/ST%2060%20RC%20%281966%29.html) the engine peaks out at around 11,500 rpm. To get there you will need to run a fuel with at least 25% total oil (50/50 should work) and keep the ring good. If you fly on 66' lines at a lap time of 5.4 you can likely get there with a 12x4.5 ish wide blade prop and fairly open muffler. If you run the 2 - 2+ -2 kind of run you could be very close to the more constant speed the ship likes. If you can get one of the Brain Gardner ABC setup it will definitely do this and more.

The ST60's were also run on pipe (Windy U) and it seemed to do just fine just watch the % oil and don't overload it.

Best,    DennisT

    How much experience do you have running ST. 60's? Tom Lay did not do any retiming on the ST.60 light case as far as I know from my discussions with him and I won several of his engines. I don't think Brian G. made any changes to the timing either. I installed one of his sets in a light case ST.60 and it was still a baffled piston. To date, I have not flown the engine yet but hope to soon. Just changing the piston and liner material won't change the run of the engine. The ST.60 is a versatile engine and was offered from the factory as a C/L stunt engine, and can handle a wide range of props in stock configuration. the ABC set up just makes it longer lasting and removes the need to find good rings for them.

  Type at you later,
   Dan McEntee

[EricV]

    How much experience do you have running ST. 60's? Tom Lay did not do any retiming on the ST.60 light case as far as I know from my discussions with him and I won several of his engines. I don't think Brian G. made any changes to the timing either. I installed one of his sets in a light case ST.60 and it was still a baffled piston. To date, I have not flown the engine yet but hope to soon. Just changing the piston and liner material won't change the run of the engine. The ST.60 is a versatile engine and was offered from the factory as a C/L stunt engine, and can handle a wide range of props in stock configuration. the ABC set up just makes it longer lasting and removes the need to find good rings for them.

  Type at you later,
   Dan McEntee

Good questions Dan and Dennis. The ABC setup opens up some territory for the ST60 that was avoided with a ring... and that is the option to run it in a constant wet 2 that would have not been possible with any kind of longevity or consistency with the ring. That, and weather you have a later K model or older ST60 will play into it too. Later heads with a thick squish band and higher comp would probably benefit this hypothetical ABC wet-2 arrangement as well. It might actually take a head gasket or two to dial it in, but maybe not. Just have to run it and see.

You don't need to run 12k to mimic a pipe setup, most guys running pipes never got near there on a 60 size setup. Most run between 8600 to 10500 depending on the size of the engine, though I did run my smaller PA40 a little harder, heh. SO an ABC ST60 running sub 10K with say... a 12.5 x 4.7'ish prop might be an interesting proposition in a plane like a TP, but someone will have to be the test monkey and go try it. My experience with ST60's all predates my switching to the PA and Pipe rigs, so, as much as I wish I could give better insight, I can only speculate. I did run a Bolly 12x5N  3 Blade? (at least that is what I tweaked it down to, don't remember the stock markings, probably started life with more pitch, and N was for Narrow blades in Bolly world)  on a ST60 for a while in an Intrepid XL... it was pretty good, a fairly flat run and didn't break much at all, was pretty good in KOI winds even, but it did go through rings rather quick... and that is what I am basing my speculation on the ABC setup upon... It was right after I lost that plane (wing folded, oops...heh) that I went to other engine packages.

Didn't Frank Williams run a ST60 with a side to rear header to hang a pipe on it on his big profile warbird test bed? (bearcat ?) His thoughts would be interesting if he was around to speculate on the impact an ABC setup would have based on his findings. My guess is, it still won't run as well as a true pipe rig, but it would be a lot better than a traditional 2/4 ST run. You might find a muffler arrangement (1/4 wave to mimic a pipe?) that'll get you close enough for 95% of pipe performance... it's always that last 5% that is hard to get, but much appreciated when you have it. All that said, it sure is a lot easier to buy something modern off the shelf, and in the long run, might be cheaper too, unless you really really like to just tinker. If you want to just go out and compete, and set it forget it, go the modern route.

EricV

[Dennis Toth]

I have two of the ABC ST60's. I know some have just used them as 4-2-4 with this setup but other options could also work. Just because it is baffled doesn't mean it can't run in a better rpm range. The ABC setup allows for better compression seal and makes it a stronger engine. I think many fliers never tried the higher rpm lower pitch approach with the older ring version. Again, I think that adjusting fuel, prop and venturi can make it a strong power plant that is simple and reliable as opposed to the 4-2-4 type run. It won't put out the power of the larger 70's but for 60 size ship it should be a good fit.

Best,   DennisT

[Will Hinton]

Thanks for the responses.

I appreciate that this is a finely tuned design and really needs a strong power delivery in order to operate to the full - as Brett makes clear.

I was talking with one of our leading flyers at the CLAPA Champs this weekend - he said that the US designs are really designed for US conditions which derive from a big continental land mass - thinner air and less wind. By contrast our home conditions include air with the consistency of pea soup.. ..and strong winds/turbulence. As a result we don't really need the very thick wing sections to generate lift.

I was wondering if I were to 'butcher' the wing section by slimming down the profile by 1/8th each side whether I might lower the need for engine power and better adapt to the thicker air (and often wet/turbulent) that we experience on this side of the pond. With apologies to the purists, I wonder whether this might be worth a try - or maybe I should leave well alone and move the kit on to someone better able to use it?

I don't expect to start cutting wood anytime soon and can find another home for the Tom Lay ST 60 - having been sold a Taurus part-kit by the same guy on Sunday - big vintage design with a huge wing but very thin section.

Thanks again

Ian

I am trying to determine just where we have thinner air and less wind!  Your expert definitely has never flown in northwest Ohio.
Our conditions here are often as challenging as anywhere on the planet.  To follow up on this statement, my Trivial Pursuit based Crosswind was one of the best high wind, slow lap airplanes I have ever flown.  Granted, my power was a piped PA75, but my lap times were set at 5.7.
If you want to find high winds to fly in, visit the AMA site in Muncie, Indiana at the wrong time.  (Often at the nats.)

[Brett Buck]

We assume Mr Hewitt isnt after a ' Top 15 ' in the World Champs .

Read the ' Thunder Gazer ' stuff ( again again again - One dosnt ' absorb ' all the minuate in one hit . )
Bretts Comment There on the Hi Drag Wing is exactly WHY the T. G. went to the Werwage T - Bolt Wing .

  Sort of - the reason you can get away with a thinner wing is that you can control the speed so much better. You can ask Ted but I am pretty convinced that we overdid the wing thickness on the Trivial Pursuit and Infinity, because we did not fully grasp the extent to which you could control the speed with the engine response, and you have so much better corner response that you don't have to worry about lift even at pretty alarming wing loading. ST60s have none of that control and you don't want to use it on a thin wing or reduce the flaps, you need the thick wing and larger flaps to control the speed and keep it from stalling.

     Brett

[M Spencer]

A widdle warning . The man said TWO RING ST 60 er  ,

THESE have a 26 mm O D Liner , AND a Short rod . As the gudgeons lower .

The Gardner A B C , is the 26.5 mm O D Liner . The lack of ' rig bars ' or one window ( Rather'n 4 or 3 ) MEANS the PORT AREA is Greater .
Reputation is More Grunt , likely need decompressing . Maybe He did some Hemi Heads . perhaps  ? .

So it wont fit . Two ring first series was WEDGE , and kicked . Next was HEMI with say 1.5 Squish . All the heads interchange .
A single ring piston & rod MIGHT go it , But being a T&L if it is , one wouldnt presume to F with it , bar ventuie & muffler .

Mr Lay Recomends 20 % CASTOR , or 10/10 Syn / Castor for masochists , Recons on doubled ring life , on castor only . 20 % .


Maybe 20 C 3 Syn in a heat wave there .

Tony Bonnelo uses the Side to Rear Header , as do others . ON HIS CURRENT S Tigre 60 .Dunno if thisisit . 3 window I believe . More Eco Nom icle . 



A G 60 ' pipe ' header'd do , well , to a aft muffler  somewhere . Tecnically I think they call it a ' ELBOW ' ,

the G-40 and  G 60 , G65 Elbow'd fit , were plenty in England once .  justincase , Tho doubt its the 1 center bolt fitting .
ACTUALLY with a 10 thou whittle , a Double Star muffler slips on , Some easier than others , for a ' No Lug ' Early series . 

Only picture of a Pipe elbow I could find ( G-15 RV ) F to R header looks like a " ? " just about .
Any Spare Elbows ? I'll have em , THANKS .

AFTER PICTURE neumero uno , , WE'RE GETTING A BIT WIDE OF THE MARK , Straight & True is the prime object .
Maybe Carbon Veil on the Flaps , and anything else too . see Bob Hunt & C V in Search .