ET-2 Mark 2

[Larry Renger]

The design is progressing.  This version has a coroplast fuselage, wing incidence, tail incidence and downthrust.

[Tim Wescott]

Oooh, pretty.  Now if only you could get a smaller motor controller, designed by someone smart enough to keep it working long enough to actually fly.

[Larry Renger]

I'm open to hearing from volunteers 

[MarcusCordeiro]

Cool Larry!

Marcus

[Larry Renger]

the first flight was rather gutsy, as I trained a total newbie.  After one lap I let him have total control and he flew it to an acceptable landing.  After staggering about a bit, he was ready for another go and did the entire flight solo. Two other non-regular CL fliers tackled the model and flew it.  No damage! 

I still think the trim could be improved with more downthrust and stabilizer angle, but it obviously is survivable as is.

Tim Wescott is developing an affordable timer and everything else is working out to be a reasonable cost intro trainer that our club can sell at our training sessions.  We will donate the cost of construction, of course but the out of pocket should allow a reasonable purchase price to those interested. I am hoping for $50, but reasonably sure we can stay under $80 with the total plane, battery, power system and charger. Certainly in line with a '60s Pt-19, fuel, battery system.

I really appreciate Eric Rule of rsmdistribution.com supporting  both this project and the ET-1 trainer.  Contact him if you want to participate. He is the guy laser cutting all the important parts!

This project is part of the Knights of the Round Circle effort to expose and alert and train kids to the sport of control line flying. Over the last few years we have trained over 500 kids on our ET-1 models.  Every once and a while a parent has come to us saying "Where do we go from here?" and we have had no good answer.  The ET-2 is our plan. A simple, ready to fly model that can be flown anywhere, and as a total system at a reasonable cost.

I hope this catches on, as I don't see any other programs on the horizon for wide distribution. The efforts of ourselves and others in flight training venues will not generate the interest of kids dragging their friends out to fly.

To do that they need the equivalent of the old Cox models that were available just about in every toy store. We can not achieve this, but there is still some that we can do.  The Knights of the Round Circle is supporting this effort!

[john e. holliday]

Larry, how do we thank you for what you are trying do.   I remember helping the late Dale Kirn at a NATS with the Cox PT-19's and getting people on the handle.   Also each hour he would draw a name of a person who had tried to fly and give the PT-19 package to them.   The reason I remember this most is one young man that wanted one so bad and you could tell he could not afford it.   He would stay and put up a flight each hour and volunteered to help us with picking up pieces and what ever asked of him.  The last hour was done and Dale drew the name.   The young lad was heart broken as he still did not win.  But the Dale as loud as could called the lad by name and announced to everyone within hearing distance this young lad was getting his PT-19.    By they way how many remember the down thrust that you put on the engine when first learning.   I still can't remember how many people we went through that day.   Melvin Schuette was even helping on most of the flights.   We were all tired by the end of the day. 

[Tim Wescott]

Tim Wescott is developing an affordable timer

The status of which is that it has been tested and works fine on a 5V input.  Due to an oversight on my part I specified a part (a voltage regulator) that can't withstand an input voltage of more than 6V (the battery puts out about 9V, dropping to 7V in flight).  Due to sheer laziness compounded by a lack of parts, I never tested it in the final configuration.

The regulator would hold together with the battery plugged in, but as soon as the motor started up -- POOF!

Fortunately, the regulator that I specified has a pin-for-pin replacement that'll solder onto the board without modification, and that part is good for a 16V input and only a couple of dimes more expensive.

I can't help looking at this thing, and at the Air Hog chuck glider that I have, and thinking that if you could make 10,000 of these at a time, you could mold them out of foam and put them in stores for $50 to $80 a pop.  If only you could sell enough...

[Duke.Johnson]

Larry
Didn't you post the drawings for this at one time?  Have you tried the pattern with this plane?  I have a new guy (RC guy) who my son is going to build a plane for and this looks like the ticket.
Thanks
Duke

[dave siegler]

What is the rational for all the down-thrust, and tail incidence? 


The ones we use are all 0 -0 -0

[Duke.Johnson]

Never mind I found the drawing. Thanks

[Larry Renger]

The ET-2 flies a flawless pattern...it takes off the ground, flies level and lands. IT'S A TRAINER!

You want a patten, buy a Sky Sport, Sky Streak or Baby Magician, all my designs capable of competitive performance in the 500 point range.  rsmdistribution.com , Eric Rule kits them all along with the ET-1 and 2.

As far as the incidence settings and trim, I am dealing with a model that has about 1/2 the thrust compared to weight. And a wing loading that is rather high. There is no margin for error. The model has to trim out like a free-flight, not a stunter.  Trust me!

[dave siegler]

Larry, that picture is the trainer we use to fly about 2000 kids in a week at EAA ariventure.   The Engine is a Norvel 061, and some of engines have been in service for 5 years.  They are not world beaters.  The prop of choice is an old top flight 6x2.  Not real efficient.   

They wont loop or wing over, can only do gentle climbs and dives without mushing in.  They glide like bricks, but are not crash-able,

So you went with the down thrust and incidence due to the low power, not stability reasons? Like running a more forward CG?

[Avaiojet]

What is the rational for all the down-thrust, and tail incidence? 


The ones we use are all 0 -0 -0

Dave,

Really nice looking model. I see you're using the Ringmaster airfoil.   

[Larry Renger]

The way to get a good glide is to balance the thrust angle against stabilizer trim so that the wing continues to fly at a reasonable angle of attack after the power quits. The alternative is to use a large elevator, something I don't want on a trainer.  I am trying to achieve a free-flight model that happens to fly in a circle and can have its altitude adjusted by the pilot, but not too much.

[dave siegler]

Ok, you set it up for a good glide with the limited horizontal surfaces, then cranked in enough down-thrust to fly level under power.

The Kidventue airplanes are nose heavy, have limited power and elevator command, and glide poorly.  But we hand launch over grass so it is fine.

You are probably on pavement, and need to make a smoother landing. 

[Larry Renger]

Yup, I just cant stand a plane that is uncontrollable except under power. I am building the Mark 3 as soon as I get some parts from Eric Rule. Tim Wescott already has a set of those parts as a thank-you for developing the timer.

We may need to buy a moderately large number of the timers. Anybody out there want to buy one?

[Luiz Carlos Franco]

I would buy one timer. More than one depending on the final price.
Remember, The E-flite timer (the simplest avaialable till now) is no longer sold.

Thanks

Luiz

[Tim Wescott]

I would buy one timer. More than one depending on the final price.
Remember, The E-flite timer (the simplest avaialable till now) is no longer sold.

It's not a timer like the others on the market -- it's an integrated timer & power switch for a brushed motor.  So it works where Hubin/Renicle/Burger-style timers won't, and it won't work where those style timers will.

I think Will Hubin sells some of his timers pretty cheap, if you want a timer for a brushless/ESC combo.