Bobby is so great.  I talked to him at VSC a little.  Too many people at times to converse.  He told me he is completely sold on electric.   I guess being able to fly in the neighborhood at 0700 hours is good.  Yes he won Classic again and after the banquet he stated he was told to not bring the same plane again.   I think he said it was 9 years old.   After my experience again with needle settings maybe electric might be the way to go for all out competition.   But, I still like the sound of a good engine run in stunt.  I was kind of startled when the electric entry in Classic cast a shadow as it flew over head(really I was outside the circle).  I didn't even hear the prop noise.  But, Bob asked if I had been keeping up on this twin build.  That is why I am here reading it again on Sunday morn before Church.  Also waiting for the final result of his Oosama plane(chech spelling)  could be Usaama.    He is a power house and his little talk after receiving the Keeper Of The Flame Award was inspiring.   

Bobby is so great.  I talked to him at VSC a little.  Too many people at times to converse.  He told me he is completely sold on electric.   I guess being able to fly in the neighborhood at 0700 hours is good.  Yes he won Classic again and after the banquet he stated he was told to not bring the same plane again.   I think he said it was 9 years old.   After my experience again with needle settings maybe electric might be the way to go for all out competition.   But, I still like the sound of a good engine run in stunt.  I was kind of startled when the electric entry in Classic cast a shadow as it flew over head(really I was outside the circle).  I didn't even hear the prop noise.  But, Bob asked if I had been keeping up on this twin build.  That is why I am here reading it again on Sunday morn before Church.  Also waiting for the final result of his Oosama plane(chech spelling)  could be Usaama.    He is a power house and his little talk after receiving the Keeper Of The Flame Award was inspiring.   

It's Bob that doesn't cast a shadow.  You didn't see him near any mirrors, did you?  Same deal; he doesn't show up in mirrors. 

Okay, VSC is over and I'm getting caught up on wing orders at RVP, so it's time to get back to the electric twin, Second Wind!

I've fitted the blocks to the nacelles and even carved and sanded the top blocks on each nacelle. The bottom blocks were tack glued on last night and I carved and sanded one of them to near final shape. The other one was left un-carved to show the sequence of the work.

I cut the intake shape pieces from 1/64 plywood and then glued them permanently to the front of the cowl and right on the center line. I carve and sand to conform to the ply pieces and then remove the blocks and hollow them out and then open the hole in the plywood pieces and leave about a 1/32-inch wall to hold the edge of the opening and keep it clean. I should be able to get all of that done tonight.

I couldn't resist placing the nacelles in their approximate position of the wing for a mock-up photo or two. Seeing what it is going to look like keeps me going!

Enjoy the photos – Bob Hunt 

Thanks, Keith:

Yeah, I'll be very upset if someone asks me if it's a modified Nobler...

Bob

Looking absolutely FANTASTIC Bob!!!!  Keep the pictures coming!

It's a twin. So, it is obviously a modified DC-3!

Looking great Bob. Keep the pictures coming.

Looking smooth..

Must be easy being bob hunt........ cruise out win the vsc for the hundredth time, float home, keep working on a simple little project, electric twin with full retract system, and be as cool as ice doing it.

Pure class all the way. 


When do you hope to :

A: Start the paint prep work
B: Have it buttoned up for Pre-flight ?

HAHA

I'm not really that familiar with the retracts thing - interms of how they intergrate with a model - so It will be interesting to see how they work with your twin and to see them 1st hand.

The perception I get (about you ) is from seeing the work - it looks orderly, organized, clean and consise - with a very slow deliberate methodical approach. Like you have all the time in the world to get things done! - I havent even painted my Nats model yet and I feel Im the only one "behind"

Re: the Pitbull - Thanks - Its what dad is going to fly in advanced - he likes it - As i wrote - its basically a nobler slightly modified with more of today's thinking design wise.

Hey you can credit a new design revolution .... and steal that from me - after all I stole - blatently I might add the caprice colour scheme just in Green /gold 

I often check out this thread - Seeing this ship fly at the Nats is certainly in my top 3 things I want to do a the Nats.

Keep it up ,you continue to inspire everyone.

I got a lot done this week on the “Second Wind” twin project. I finished carving and sanding the nacelles and hollowed the blocks. The main thing that has been on my mind throughout this project is how would I accurately mount the nacelles to the wing? I wanted to insure that they would be accurate to each other and also accurate in respect to the rest of the airframe.

In looking at the nacelles I realized that there was a rectangular opening at the bottom of the nacelle crutches. I figured that I could make rectangular pieces of foam onto which I could mount the nacelles and then in turn mount the foam rectangles to a base board in the correct location for perfect alignment to each other.

In order to insure that the thrust line was parallel to the centerline of the airplane I used the fixture pieces that I made to align the motor mount plates to the nacelles and blocked them up to the appropriate height and the angled scribed lines on the foam rectangles in the proper locations. Then I glued pieces of wood to the sides of the foam rectangles along those scribed lines. When all of that was done I could simply drop the nacelles onto the foam rectangles and the bottoms of the nacelle sides would rest atop the angled pieces of wood and hold the nacelles in perfect alignment.

Next I measured the width of the fuselage at the front and back of the wing and halved that dimension. I marked either side of the centerline on the fixture with those dimensions and also computed how far aft the back face of the wing trailing edge was from the rear face of the rearmost nacelle former. I scribed a pen line across the fixture at that point to allow me to adjust the top view “skew.”

I know all this sounds a bit complicated, but it is not. My friend, Buddy Wieder and I engineered and built this entire assembly fixture in about two hours and had the airframe sitting in place for a final fit. We adjusted the airframe as required and measured all around several times to insure that the entire airplane was in virtually perfect alignment. It was accurate all around to well within 1/64 inch.

I will now finish working on the nacelles by installing the lower front chin pieces with the cooling baffles and installing all the required holdowns to the lower removable nacelle pieces that will cover the retract units. I’ll even dope and carbon the nacelles before placing them atop the fixture pieces and realigning the airframe atop them for permanent assembly.

The accompanying photos should make all of this clear. Hey, this is fun!

Bob Hunt   

Atsa nice!
Glad to see you put Buddy to work!
  Dean

 Very cool plane Bob and it's looking great. Looks like most of the "hard" work is done. Glad to see your back on it. What's your timeframe goal to have it done?

 I also caught your Mig 3 mention above. I've always thought that plane would make a super cool model but yeah, gotta keep that sleek nose to have it look "right".

Thanks for the kind words, Wayne. I'm hoping to be into finish by the end of next week. I'm pretty energized by getting past the problem of accurately mounting the nacelles. Hopefully I will be able to keep the juices flowing right on through finishing.

Phil Granderson gave me a great paint trimming idea that picks up many of the cues from my Genesis and Caprice schemes. Yes, there will be some bronze on it!  

The Mig 3 just may be the next one up on the bench, although I am starting to like the looks of twins! We'll see. If I do build the Mig, it will have retracts!

Later - Bob  

Thanks, PJ, I think...

I'm pretty sure that I'll be happy to stay with twins for a while, although I have given some thought to a tri-motor set-up with counter-rotating props on the motors in the nacelles on the wing and contra-rotating props on two motors in the fuselage (four motors and four props...). Of course a dual pusher-puller contra-rotating setup on the wing (front and back...) one contra-rotating setup in the nose of the fuselage (if you are counting, that would be ten separate motors and props...) might be a doable option.

Yes, the men in the white coats are scheduled to arrive at any moment...

Later - Bob

It was meant as a compliment....

Most twins I've seen were scale style jobs...... the french twin at the worlds.. windys' twin's - and a few other twins which escape my mind ( Gordon delaney perhaps... I cant QUITE recall.. ) I think it was called Too much - or Too trouble... Soryr for being vague on that.

What i mean was classical AMA Stunt ships have flowing lines and stylish cue's this is the first time I've seen a twin that takes its styling lines from classical ship shapes. - Very impressive.

Okay, over the weekend I got a bit done on the Second Wind.

I decided to do as much as possible on the nacelles before installing them on the airframe. I figured that it is much easier to do intricate work on such small parts with them off the airplane. I installed the forward chin pieces with the airscoop openings completed (Done in the same manner as the cowling I used as an example in my recent MA CL Stunt column...), and applied three coats of dope to the nacelles. Last night I covered the nacelles with .2 carbon mat, applied with very this dope. This morning I lightly sanded the carbon and applied another coat of dope.

I put the nacelles onto the alignment fixture and slid the airframe in place for some progress report photos. Note the lower cowl pieces that are positioned in front of the airplane. Obviously, with the nacelles on the alignment fixture, I could not also install the cowl pieces. Trust me; they fit very nicely!

I also stuck on a rough template of the possible nose block shape. The jury is still out on that shape and size, and I will try several different shapes until one just "jumps out at me."

Both Phil Granderson and Steve Buso came to the rescue with some "good" 00 silkspan, and tonight I will cover the outer wing panels. As soon as they are covered and have had a few coats of dope applied, I'll permanently mount the nacelles and install the main gear retract mounts. The nose gear retract mount is already in.

After that it is just a matter of cutting a nose gear strut and wheel clearance hole in the lower nose shell and also cutting clearance holes for the main gear struts and wheels in the lower nacelle cowl blocks. The last things that will be required before all out finishing can proceed is to decide on a nose block shape and carve and hollow that and then fit the forward top access hatch with the simulated forward canopy section in place and install hold down magnets or screws. (I lean toward screws for added security...)

If all goes as planned, I'll be into finish by the weekend!

Later - Bob Hunt    

Great build sequence Bob. I like your solution for aligning the nacells. You are absolutly corect in paying great attention to the alignments with multi engined stunters.

Gordan came up with a method for doing the alignment, that was slightly different, but worked fine. I don't think his twin would have flown as well if the alignments weren't right. 

Looks like some "seckret potion" you got in that there jar.

Seriously now, you use nitrate or buty to attach the carbon fibre ?  
Also can cf be worked around compound curve wingtips (and your nacells in this case), or do you have to piece it ?  
Would there be any benefit to putting a layer of cf on top of the silkspan, or is that a bad idea ?

Hi Allan:

Well, I used to use nothing but nitrate dope to attach the carbon and the silkspan, but I had a bad batch or something one time and it scared me back to butyrate, and I've been very happy since. I do custom "adjust" the shrink of the butyrate with a plasticizer (I use Dave Brown's Flexall). That's a trick that Billy Werwage taught me...

I find that the carbon will go around a moderate compound curve, but will require slicing and overlaying if the curve gets too extreme. No worries as you can easily sand any overlap humps out. I like it way better than silkspan for solid surfaces for just that reason. If you overlap silkspan you will have a hard time making the surface smooth again with no overlaps showing.

I do not see any need to put CF over the silkspan on the covered wing. I do, however, carbon the entire wing prior to covering with silkspan. I remove the carbon from the open bay areas by sanding against the edges of the cap strips and the wing framing (LE and TE sheeting) to insure that there are no "sharp" edges that might later cut though the silkspan. The carbon adds very little in weight and it adds tremendous strength. I know that others do not believe that the carbon adds much strength. I feel that it adds a lot of torsional rigidity to the airframe. I also feel that all the planes I've covered with the .2 ounce carbon mat fly better in the wind than did models that I've owned that were not carbon covered. The carbon adds much stiffness.

Later - Bob Hunt  

Ahh, I see.  I usually keep notes on where I am in regards of how many coats of dope have been applied, etc.  The older I get the more notes I use.  

I do not see any need to put CF over the silkspan on the covered wing. I do, however, carbon the entire wing prior to covering with silkspan. I remove the carbon from the open bay areas by sanding against the edges of the cap strips and the wing framing (LE and TE sheeting) to insure that there are no "sharp" edges that might later cut though the silkspan. The carbon adds very little in weight and it adds tremendous strength. I know that others do not believe that the carbon adds much strength. I feel that it adds a lot of torsional rigidity to the airframe. I also feel that all the planes I've covered with the .2 ounce carbon mat fly better in the wind than did models that I've owned that were not carbon covered. The carbon adds much stiffness.
Later - Bob Hunt  

I was thinking a layer of cf on top of the silkspan would add a lot of puncture resistance for a small weight gain.  I recently got careless while handling one of my models and poked a hole in it, and it is covered with polyspan (regular)..      I tried the lite version of polyspan a while back after talking with you, but I didnt like it.  Took too many coats to get it filled, seemed like more work for little if any weight saving.   Why did you choose silkspan for the twin vs polyspan ? 

Bob this plane is so cool to read about and all the cool things about it!!!  I'm really anxious to hear how the gear are going to retract! 

Hi Matt:

Thanks for the comments; I like seeing the photos of your new ship, too!

The retracts for this one are very simple. The mains retract forward into the nacelles and the wheel nestles just in front of and slightly below the leading edge. There is about 1/8 inch clearance between the wheel and the wing when retracted. The nose gear goes straight back. I will have narrow fairings on the gear legs to give them some shape (Nothing more unsightly than a piece of plain music wire sticking down...) and small doors that will fit into the opening after the gear is up.

The operation of the gear is simplicity itself, The E-Flite units are electric and have a motor attached to a worm gear. The Hubin 2-channel timer allows me to sequence the gear up around 10 seconds after full power-up and then extends them 5 seconds before the motors shut off. Dean Pappas and I had them working to perfection on the bench a few weeks back and they went up exactly on time and down exactly on time as programmed. They run off of the actual flight battery, so it's a matter of hook them up, sequence them and, well, forget them (at least that's the plan...).

Here's a shot of the bottom with the nacelles installed.

Later - Bob
    

Hi Wayne:

You are sooooo right! It seems like this one took forever to come together, but it is now moving very quickly.

I used good old 00 silkspan to cover the open bays. I have two very good friends who sent me a few sheets each of the "good" stuff. (Thanks again to Phil Granderson and Steve Buso)

I'm done for tonight on the twin, but tomorrow morning I will make and fit the main gear retract mounts. Shouldn't take too many more sessions until I'm into full-blown finish mode. 

Later - Bob

I'm pretty sure you would be sorry that you covered over silkspan or Polyspan with carbon.  
 

Why is that, because of the extra weight ?

By the way, I just weighed the airframe with the nacelles and the spinners on and the wing covered with silkspan and one coat of dope, and with the stabilizer, elevators and flaps covered with carbon... Drum roll here please... It weighs 25 ounces! I'm ecstatic! 

I'm on target at this point to have a 58 to 60 ounce ship, with the battery (fuel) on board! That's equivalent to a glow model at 52 to 54 ounces without fuel on board! 

Bob