Topic: Stearman - Ziroil 77" with Seidel 770ST radial

Paul, you're doing a grand job mate

Mark

Absolutely 

Day 23 - 77 Hours
   Not a lot of work done over the weekend too busy flying 

Made and installed second servo wire tube, bent and clamped last wing tip and fitted same more sheeting to wing, should be ready to join two halves in the next week or so (looking forward to that)

A friend from my model club gave me some diluted Ammonia to try, apart from the overpowering smell almost chocking me I found it no better then water?

Paul

PS thanks for the encouragement I'm getting to the point were I needed it, 

The ammonia needs to be concentrated to work ,if you think the dilute pongs try concentrated!! .I nick some 0.88 from the science department at school  , which is as concentrated as you can get. I think cloudy household ammonia,which used to be available from old fashioned  iron mongers  will work as well.

Alan

any signs of the engine yet? 

any signs of the engine yet? 

Yes its out of the harvard and sitting on the bench behind me, begging to be bolted on.  But before I get to it, I want to have the gear in and the wings fitted, so quite a while yet before you will see it on the Stearman.

If you haven't seen it before, look back at the first page of this threat for pics and run in video.

Paul

Day 24 - 79 Hours

   Spoke to Bell Air yesterday, expecting my undercarriage next week, so hoping to get the wings finished off and joined so I can get back to the fuz. 

A couple of hours spent last night, on a little more construction on the last aileron and a rough sanding on the wing tip, used a little more filler than I would have liked but had quite a large indent on the tip, I had to apply about 2mm in one place, I hope it doesn't show too much through the covering.

Paul

Hi Paul,

Still looking good from here  , If you think your filler may make a difference then balance the whole airframe laterally. It is a pet bee in my bonnet that everyone spends a lot of time with the CG yet never mentions the lateral balance 

To my mind this can be almost if not as destructive to a new aircraft as the CG !

Day 25 - 82 hours

Second aileron completed, sanded and hinged. I intend leaving the final sanding and shaping until wing halves are joined.

Paul

Hi Paul,

Still looking good from here  , If you think your filler may make a difference then balance the whole airframe laterally. It is a pet bee in my bonnet that everyone spends a lot of time with the CG yet never mentions the lateral balance 

To my mind this can be almost if not as destructive to a new aircraft as the CG !

Yes "kcman", I will do this when finished build, I guess before covering, although the filler used is very light. Never done this before do you have any suggestions on how to balance the plain lateral when finished?

Paul

Hang it from the top of the fin and the crankshaft................if one wing hangs low, add weight to the light tip intill it hangs level.

Day 26+27 - 90 hours

  Progress is a lot slower now as all the big parts are together and working on smaller details like servo install.  I have received the landing gear one of the welds on one of the flanges is only attached by one tack and two are broken away, I'll have a closer look to see if this is a problem or if I can fix it myself.

Installed second aileron servo and servo horn, cut and installed last shear webs.  Joined the 2 wing halves together using PVS glue, after sanding and fitting any joining pieces that don't quite marry up. Each tip is raised of the bench by 7/8" to set dihedral, this relates to the angle on the 2 ply joiners installed in the first wing earlier.

I'm leaving all the final sanding and finishing until, I have done all the fitting to the fuz and am ready for covering, as I guess I am going to dent and mark the wings in this process.

I haven't got much done over the last week as I have been a little pre-occupied with another new toy purchased    See pictures

Paul

Hi
Given the price of the landing gear I would return them.

If they are aluminium you will give yourself problems trying to repair them,

I have tried techno weld and another better variant yes it can be done but sometimes things just wont go right,

A Tig welder is the best option

Given the stress the legs will go through they must be good

Send them back
Take your time no need to rush 

Bert
 

Here is my 77" Ziroli Stearman built last year.  Its good to see you taking the time to share your experience

Here is my 77" Ziroli Stearman built last year.  Its good to see you taking the time to share your experience

Hi "me"
  Nice looking model, I will be very pleased if mine comes out looking half as nice as yours, is that the OS up front?
I thought it would be very helpful for me, plus any other balsa virgin to see it done from a rookies stand point.

Can I pic your brain<  What prop are you running?  What RPM do you achieve? whats the power like in flight? and whats the all up weight?

Sorry for all the questions but I am very interested in learning as much about how it will perform with my radial, before it leaves the ground.  The Seidel has about 4hp but only achieves 5000rpm, I think the OS runs at about 7k with the same hp.

Paul

Hi  Paul
The model weight is just under 24 lbs, powered by the OS Sirius Fr5-300 which is more than enough, I am using a 20x8 prop appox 6500 rpm  ( which according to this other web site ) gives 24lbs thrust but it is still early days I thinking of trying a 19x10 it flies on half throttle.

Try RC universe.com then enter ( Everything Radial ) plenty of information on your engine

The model is covered with Ceconite and sprayed using 2 pack with a flex additive

Jon

Anyone going to the Nationals this weekend?

Paul

Hi Paul,

Yes to the Nationals, will be there Saturday morning through to Monday evening weather permitting

Hi Paul
Look over your sholder if I ain't there turn the car around as you have left me behind
Bert

I must get back to this model. Now I realise how people spend years building a model like this, 2 months on the bench 2 years on the shelf.  I will get on with this over the coming winter.  Come back soon.

Day 28 - 93 hours

WELL IM BACK IN THE SHED AFTER A VERY VERY LONG TIME AND FOUND THIS.

So back on the bench with the Stearman gluing the wing seat supports to the side of the unfinished fuss, this is a lot easier than it looks, soaked in water for a minuet and then dried it off clamped to the plane then re fitted with glue and lots of clamps.

Oh there you are

Good to see your back in the seat.

Keep going it's the only way forward, you will be rewarded with jealousy of the ARTF crowd. 

Day 29 - 96 hours

Wing Seats,

Placing the wing in the wing seat hole on the ply supports I have sanded then down one to fit the wing shat a bit better and 2 to level the wing with the tail, I used a strait egged resting on the tail and visually lined the 2 up.

once happy with the fit I applied wood glue the the ply supports and positioned the wing seats (Thin ply supplied with kit) I then used the wing itself as a clamp/form and then added wait ti the underside of the win as its upside down.

Day 29 - 97 hours

Rudder - did this as I can't work on the fuss untill tomorow when glue will be dry.

Just knocked this up using cyno and a bit of wood glue very strait forward once you have found all the parts and sanded to fit.  I think there is a lot more work in this rudder I will come back to it later.

Day 30 - 99 hours

Cyno is your friend.

Wing seats, I cut and sanded the outer edges from the wing seats to fit the side of the fuss, i will finish off properly before I cover.

Now wondering what to do next I thought I would have a go at using cyno for the stringers, wow, I replaced s few that i was not happy with and installed 14 new ones most full length in about 20 mins, just wicked a few drops in a puff of smoke DONE!

So this last 2 hours consisted of 1 1/2 hours on the wing seats and 30 mins on the stringers, I will need to go back and fill in the gaps in the formers that were not the correct size or position.

PS any opinions on mounting 2 elevator servos in the rear of the fuss?

I'd keep them all up front.......2 servos in the back end of a model with a VERY short nose will mean nose weight 

Phil

I will be putting a large radial up front so I was thinking of getting some weight towards the back?

How does your radial compare weight wise to the petrol engine Ziroli suggests?....if it's approx 1lb or more heavier, you may be OK

What is the nose to tail moment? (distance from CG to the nose & CG to the tail)........if you have a moment of say 5:1 and the 2 servos weight 50-60g each (120g total), that's 120g x 5 (600g....approx 1lb) needed up front to counter their weight.

That's a lot of extra weight to carry when you could just fit them inside the fuz close to the CG.

Phil

Well, the Seidel is 2.6KG and a Zenoah 38 modern equivalent of the suggested power plant with no pipe is 1.6KG making a difference of 0.8KG or 1.8lbs so I guess I could do with the extra weight at the back.  I hear what you are saying about the extra load but I am only building this plane for a home for the radial.

I'll have to take it easy when flying.

....should be OK then.

Phil

I'll have to take it easy when flying.
LOL
No chance

With so much wing area  do you need to worry too much about it
Could this not be tackled at a latter stage in the build.

Day 31 - 100 hours

Elevator servos install, I have elected to put the servos in the tail now as I will be covering them with wood work soon.  Putting them in the rear end will help with the heavy engine.  Used epoxy hear as they will be upside down and subject to vibration, don't want to have to revisit and repair later.  I will work out a hatch afar for access when I'm doing the tail.

Wow its bean 100 hours work since I started this and I guess I'm only a 1/3 way through or even less, still enjoying it after a very long break from the build, I know know how some people say they spent years building 1 model, as I will be doing the same

Your stearman is looking fantastic! I had a Royal kit given to me and had to lighten it up quite a bit. I wasn't the orriginal builder of the model but took around 2lbs of covering off of it. I've also rebuilt the landing strutts all of this to make it look more scale and hopefully lighter. So in an attempt to keep it light I've opted for a covering called light span. I get it from balsa mart. It can be a bugger to work with and you go against the grain on the wing. meaning the lite span travels the length of the wing. A friend told me otherwise and I now have to strip my wing again. You can see some photos in the general area of this forum if you like.

Looking forward to seeing her completed. Keep it up.

Day 32 & 33 - 107 hours

I missed a few bits after studding the plans a little more closely, oops

A few blocks behind the wing and a couple of pieces of ply for a the stab support.

I have also made the Ns for the outer win supports.  I made these from a light ply and balsa sandwich then sanded then to an airfoil shape, this part take a lot longer than anticipated 6 hours

Day 34 - 109 hours

Wing and stab angle. 

I borrowed a wing angle gauge (Incidence Meter) from a friend,(Thanks Bert), leveled up the plane with the wing attached and made the wind flat, 0 degrease and then sanded the stab seat to give me 1 degree of incidence, so the front of the stab is higher than the rear,  I have spelt this out as I didn't know what positive and negative incidence was until I built this plane.

Looking good
Don't forget to fit gauge on same side when aligning top wing.

Will do. Off to Florida now for a couple of weeks so don't expect to see anything for a while.

Day 35 and 36 - 121 hours

Fitting top win, what a bugger of a job.
Decided to go for aluminium cabains in stead of persisting with the piano wire heated or not.

Glued using epoxy two 5mm ply strips inside the fuss box to braise the cabain fixings, drilled holes in the top of the box to take four 3mm screws and then drill the lower part of the cabain struts and then larger holes in the top.  Over layed the aluminum strips on the plan and bent accordingly to fit, then tried them on the plane for fit and all lined up very well.  The problem is when I measured the angle of incidence Found that it was showing 0 degree and not the required +1 degree.  I did this 3 times before I got it right.

Getting this right is a real pain remembering you also have to get it parallel with the bottom wing and strait.

Need to re make the N struts as the ones I have already made from the plans are 15mm too short, so I have ordered up some hard wood for the job.  I guess a pro would have got this bang on the first time.

Done now.

Day 35 and 36 - 121 hours

Are you the narrator from big brother? 

Looks ace BTW 

Muds

Are you the narrator from big brother? 

Looks ace BTW 

Muds

Funny but no, I'm a designer.  LOL

Still Day 36 - 123 hours

Tail post, rookie error number 4 at least I think.

I fitted the tail post a few days ago and now I am looking closer at the rear end I realise I should not have, as it needs to be shaped, Bugger!  So I now need to shape it off the plane and then fit it, this will be a lot harder than doing on the plane.  I have made the balsa block by gluing two pieces together with aliphatic as it will need to be sanded to shape.

While waiting for the glue to dry I have glued the file wall to the front of the fuss, using epoxy and dales. A friend has advised me to drill holes through the fire wall and the front of the fuss and then while gluing, from the front tap in dales also fixed with epoxy, in readiness for the balsa covering to the front of the fuzz. , Cheers Bert.