Nice job on the finishing. Now I wish I did the traditional colors too.

My Mini Taurus is 70% and 50 inch span, I only have 350 square inches of wing area.

Mine weighs 32 ounces and flies scale like. Can I say that?

Paul

Cool! I've got to learn how to do that. Sounds fun.

After all is said and done, the 28 FSR might just be a perfect match. Fly it with the 28 and save your money.

David.

Hmm... alright, things not working again. If the one has a 52" span and has 460 squares, there is no way that a 50" has 100 less - 350. It is also quite amazing to build a 50" span model to 2 lbs! There must be very little wood in there. Electric?

What's the wing root and tip chord on each of the models. The spreadsheet is fine but it can be done back of the envelope within less than 3% difference.

David.

i'd give my right arm to be able to get Aero Gloss........all i ever find are the little 1/2 ounce bottles for $5.00...OUCH!!

you did a beautiful job on it.
i think David is right on with engine selection...........but it will go with what you have.
the .28 when broken in properly was a powerful little beast that thought it was a .35

I've used the 28FSR on several planes similar to yours and it will do fine. Also had thousands of flights on my 100 inch span Twin Otter (12 lbs) using a pair of them including a few Scalemasters competitions. One of the best engines OS ever made. Looking forward to your flight reports! Nice project.

Hey guys,maybe my math is wrong.Not including the ailerons my root is 9.75" tip is 7.75" and the span is 52" please check my math.Rob

Check out http://adamone.rchomepage.com/design.htm (I keep it in my bookmarks tool bar.)

I added 3/4 inch for your ailerons and got 494 square inches for area. 18.7 oz/square foot wing loading.

That is a great resource,Thanks! I was going to let the paint dry longer,but I am going to fly it tomorrow morning. I will update then. Rob

I believe RCM&amp;E featured a model very similar to yours in the 80's - a scaled down Taurus. They called theirs the Tauri I think. It was featured on the cover, but I'm not sure of any of the other details. <div>
</div><div>Great thread!</div>

Do you fly at Whittier Narrows?
Chris...

Hi Chris,I fly at Whittier,Prado and Santa fe. I dont know if whittier is open tomarrow (holiday?) so I will go to Prado. Are you in the area I think I met you last week at classic get together, I was flying the orange Kwik fly. Rob

Right Rob! Nice Taurus. I'm having a family outing on Monday but am looking forward to your first flight report. Take pictures!
Chris...

As I mentioned, spreadsheets are cool but back of the envelope pretty much gets you within 3%:

~MAC = 0.5*(9.75+7.75) = 8.75" (it's not exactly a MAC but it will do)

Area = MAC*Span = 8.75" * 52" = 455 sq in

If one includes the ailerons at 3/4" width:

Area = (10.5+8.5)*26 = 494 sq in

the same as calculated by thailazer and the spread sheet.

A more accurate effective wing area is likely closer to 19*25 = 475 sq in if one removes two inches of wing span to account for the wing tips. They may even be wider than that so being conservative and assuming an effective wing area of 465 sq in (the mean of the area without ailerons and that without tips but with ailerons), the wing loading at 60 oz (3.75 lbs) would be:

wing loading = 60/3.23 = 18.6 oz/sq ft

That sounds just perfect for a model this size.

I'm actually building a model with a 51-1/4" span and the exact same 465 squares so the magic number of 60 oz was already close to me... [8D]

Looking forward to hearing how she flies!

David.

Weight 3 lbs 14 oz? If wingspan is 52" then it's scaled 0.75 (original wingspan 69"), still quite fine with the .28 FSR.

Spreadsheets are cool if the correct dimensions are entered. I tell you what I have by scaling down the original:

wing span 52" (wing area below fuselage counts)
root chord (centerline) 9.42" including ailerons
tip chord (where the aileron bevel begins) 6.65"
add something for the rounded wingtips
wing area 400 sqin
wing loading 22.3 oz/sqft
(100% Taurus has 18 at 5.5 lbs,
Kwik-Fli Mk III has 21.7 at 6 lbs)

See attached top view from spreadsheet.


pd1, I would agree. 50" wing span is 0.725 scale factor, the geometry entered into my spreadsheet gives even 370 sqin wing area. Anyway, only 2 lbs weight give a very low 12.5 oz/sqft wing loading. That should make it "scale like" compared to the 100% Taurus, if not even too lightweight. For me, it depends on spin and snap behavior. If it just spins it's like the original, if it spins and snaps well it's heavier, and if it's reluctant to spin it's "too light". What do you think about that?

USTIK, my scale for the Mini Taurus was I simply picked a wing size that would allow me to carry the plane assembled in my car. Staples shrunk the plans, so I might be off on the exact scaling.

I used the same construction as the original but reduced wood sizes wherever I could.
3/32 fuse sides, 1/16 ribs and 1/32 leading edge sheet for example.

I did a build thread here: http://www.wattflyer.com/forums/showthread.php?t=19864

At the end of my build thread another person built one out of foam and it is less weight than mine.

My Taurus snap rolls and spins fine, I did eliminate the angled control horn so I have a bit more up elevator throw than the original.
I did like the way it flew, I should fly it more often.
After seeing this one and a few others I just wish I did the standard Taurus paint scheme now.

Paul

That low weight is just terrific! Considering the low wing loading, I'd indeed guess the good snapping comes from good elevator throw. Thanks for showing!

By the way, forgot to mention I'm old school, very old school, that is. I meant spinning and snapping with rudder and elevator only, without ailerons. Guess you meant the same.

Seeing this talk of 28FSR's inspired me to dig out some old photos of a plane I called the Scavenger as it started out using the bits left over from a Craft Air Scout. I built up a 9% thick wing using 3/8 by 1/8 basswood spars and no dihedral at all. This plane would do it all... snap rolls, knife-edge climb, rolls as soon as the wheels left the runway. It was under 4 lbs and about 52 inches in span as well with the built up wing-tips. Had several of these as they were so quick to build. The wing had no dowels as it nested into the fuse on the leading edge with just a piece of basswood inside to keep it from sliding side-to-side and it had a single 4-40 bolt holding the trailing edge on.

I found this pic on Rcu and liked the swept wing ,so I put the copy on my over head projector and enlarged it until it looked right.Then I sketched the outline one the back of an old set of plans.IF I had known there were a set of drawing that were even close,Would have saved me hours.I should have spent more time running the numbers wing area ,loading ect.My next project will have the math right first. Thanks everyone for your help.Rob

Interesting variation Rob. What's with the increased dihedral? I would have taken some out.

David.

I did not increase the dihedral, it just didn't look right. The wing has aprox .75" other than that I followed the drawing.I am off to the field, so I will give an update in a few hours. Rob

Hey guys,The plane made it home in one piece.First flight was a bit tail heavy,not uncontrollable just squirrely.After a couple of clicks of trim it seem to settle down.I flew a six minute quickie and landed a little fast,pulled the wing off to check if all was well,moved the batt under the fuel tank,and tried it again.I put three flights in yesterday, I think it is still in the aft CG range.I will move a few things around and try not to add any extra weight.Next weekend a friend is going to film it and I wil post it on U-tube. Thanks again for following my thread. Rob

Great Rob. Glad its flying well, can't wait to see it,
Chris...

HI
could I con you out of a copy of the plans for the .20 size taurus.
I go back to the days of the taurus, old, old, old. should I still be
doing this????

thanks
pt19 flyer

Yes, definitely keep doing it. I had an "adopted grandfather" who was building models of some sort until a few months before his death. When 96.

Andy

I don't have plans,but I can send you templates for the ribs and bulkheads.If I were going to build a new model,I would add 10% over all,this one is on the small side.