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Jun 24, 2015, 03:51 PM
Retired CAD guy
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Build Log

Top Dawg foamy Racer

Many years ago at teh Tri-Vallley RC club in South Bend Indiana we raced.
Jerry Smith of RCModeler fame took a Top Flight design and made a nice
little 3 channel racer. It used an OS .15 motor and took off from the ground.
I assure you that Great fun was had by ALL.

The design in now available to all at Outerzone as most legendary designs do.

I was contacted recently about possibly doing a foamy version of the Top Dawg
for a resurgent interest in racing at South Bend RC club.

I am presenting my modified design Foamy Top Dawg here now for discussion
and possible improvement.

I have added Ailerons to make it a 4 channel racer and a built up foam wing.
Although that final part of the design is still up for grabs.

The goal, as usual , was Good, Fast & Cheap.
This is entry level racing and the rules for the current level of participation
are on the SBRC site.
I expect to see some changes there to accommodate this new design
IF it proves out to be a good racer.

I am thinking 4 cheap servos, an $11 motor and a low end 40 amp esc to be safe.

The next fe posts will contain pix from my 1st build which is still in progress.
It was too nice out today to NOT Fly what I already have built.

Anyway, I have decided to make yet still some more changes to what you will be seeing shortly.

Of most concern is whether to do a super simple flat foamy wing,
or a "built up" of sorts type of wing, like ...
KFM(xxx) or TWO layers of Depron over a spar or Armin or or or ...

Next are the little

thats my story and this is where we'll talk about and share pix and ideas ! :-)
Last edited by birdofplay; Jun 24, 2015 at 03:56 PM.
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Jun 24, 2015, 04:15 PM
Retired CAD guy
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Yet still more pix

I have changed the CAD drawing to reflect a widening of the rear of the fuse
to allow for a better 45 deg brace mating all the way back to the Rudder hinge line.

That's what will be cut on the next prototype.

I've also added Vert Fuse Doublers to the mix of parts in an attempt
to stiffen up the nose.

The current sheeting is getting Full.

I also wonder about the efficacy of the little fingers of foam that surround the engine which feign the profile shape of the fuse. ?

I just wonder if they should be eliminated because they are going to get broken off anyway. Thats just a fact of life on the racing circuit.
Jun 25, 2015, 06:09 AM
Foamies rules

Do you ever sit stil . So many nice designs one after the other.
Take me ages to fully desing a plane.
My AutoCAD skill are ok but its nothing compared to you.
Must be nice to be retired.

Keep up the good work will follow closely as always.
Jun 25, 2015, 10:27 AM
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Unfortunately Sitting Still is what it takes to do the designs in CAD.

I suppose it beats mowing the lawn.

I'm doing this too
Last edited by birdofplay; Jun 25, 2015 at 10:51 AM.
Jun 25, 2015, 06:47 PM
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But ...

1st flight was a trim nightmare and I burned out both the esc AND the Motor :-(

I had checked the amps on my watt meter but it certainly did NO indicate anything like that !
Maybe the motor went an TOOK the esc with it !

I I upped the ante and slapped on a 2212/6 and a 40 amp esc.

This was MUCH more TOP DAWG like , if memory serves me. ( 20 yrs ago !!! )

More testing tomorrow and I "MAY??? " edit the vids down to something watchable
and get em up for your viewing pleasure.

So the score is
2 Flights - No broken planes - a few parts trashed.

My initial reaction:
Try a very light wing"ed" version and keep everything under 1 # . Possibly less
That'll be the next version.

So whatdayasay ???

Do we go with a light agiler racer with low cost power parts like a flat winged , Lower KV, fat propped, park plane
Do we beef it up and fly rocks at ludicrous speeds ?
Do I go the full Top Dawg Fuse and Thick wing but in Foam ?

Decisions decisions decisions


Hoosier Cutout Service
Jun 26, 2015, 12:39 AM
Foamies rules

I do agree, disigning in CAD takes alot of sitting still. Lets just say you are keeping buzy .

Personaly i like full fuse planes the best. Far more natural looking and it keeps al the electonics nice and clean.
Ripped out several wires due to not so pritty landings with my profile ones.

Maybe a twin option? For park flying a single layer fuse and for hard core speed doubble it up. Two layers of MBF is already alot stronger.
Jun 26, 2015, 01:20 AM
Wake up, feel pulse, be happy!
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I would go with a full-fuse design aimed at some actual speed. It doesn't need to be a blistering-fast rocket, but it does seem kind of sad to take a model with a racer's pedigree and turn it into yet another slow floaty flat foamie park flyer, homie.

... and if you can say that last bit as fast as the TD flies, it's probably moving too slow
Jun 26, 2015, 07:16 AM
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However, when design requirements come along ,
it's always brought up that COST is an issue
as well as Build Time.

Those requirements tend to favor the notion of
attracting NEW BLOOD into the sport.

Top Dawg racing is fun yet entry level and not as cut throat or competitive as
the sanctioned versions of racing.

This latest Foamy version is suppose to make Entry level folks more willing
to get their feet wet.

I present my latest pdf plans for review.
Jun 26, 2015, 08:22 AM
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How about doing a hybrid with a BOX section fuse on the bottom
and a Profile upper fuse.

Box section could have tabs and slots for self alignment and easy quick build.

Wing could be Flat or Built up

The nice thing is that this concept is no more foam than all the doublers and stuff on the profile version. See pdf of this version

Plus is would HIDE all those messy electronics
Last edited by birdofplay; Jun 26, 2015 at 09:28 AM.
Jun 26, 2015, 12:00 PM
skumgummi dave
Nice design work Bob!

Jun 26, 2015, 12:02 PM
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The Judi flown as a racer with a canopy is going to be here in 45 min
(1 min 49 sec)

Thanks Dave.

I also JUST got in another Top Dawg flight before the rains came.
I will be editing the vid and it WILL BE up yet this afternoon.

Using a 6x4 prop and a 1300mah 3cell pak it was VERY MUCH better than yesterday's maiden !
If Profile is the way we want to go then I believe that WE are there with this design or maybe the ver 3 .

I'll build a Ver3 and Maybe even a Ver 4 Hybrid soon.

Stay tuned :-)
Jun 26, 2015, 01:26 PM
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Top Dawg day two testing vid will be here in 45 mins
TopDawg V2 foamy profile version (3 min 45 sec)

Comments ?

thanks for watching

Hoosier Cutout Service
Jun 30, 2015, 08:14 AM
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After some flying and thinking I've come up with a few improvements and also want to try a
a NO FOIL wing like the 3D guys sport.

I also am using a much lighter thin walled 6mm CF tube.
I expect this version to have less weight.

Even so I've added more front doublers and widened the Horizontal fuse sides
at the rear for better intersection of the stiffeners.

This goes together so quick that you could be flying in a couple of evenings.

Hoosier Cutout Service

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