Guillows Stuka

[Erfolg]

I have started with cyno to hold the formers upright. On L1 I have used PVA, as I needed time to locate and then pins.

 

For me this is a major change. I would expect that it is similar for most RC modellers of the Balsa age. It is surprising how lightly built these models are compared to RC models. In comparison to ARTF assembly, it is a very different technology in my opinion.

 

I have managed to break a few formers just holding the former in place, whilst the cyno goes off.

 

It will certainly be very time consuming , building this model.

[Shane Sunday]

Ah yes it is but as she comes together it becomes worth while.

[Erfolg]

I have now cyno'd the fuz together, here are the pictures

 

As can be seen the weight is at present 30gram.

I do have a few pictures of how I got to here, but not downloaded.

For me this is very different to my typical RC build. It is somewhat delicate process, compared to sheet sides, with ply lamination's re-enforcements etc. It all goes together really fast. Without cyno, balsa cement wold be needed, if sticking the stringers on, is not going to take an age if PVA is used.

 

I personally do not see the present structure as viable as a RC model, even though I have re-enforced the formers. I intended using the techniques that FF use, although achieving there low weight and high strength may be a stretch for me. The technique I hope to replicate is shown Here! in "Mikes Flying Models"

 

It may be some time before you hear from me again. I would welcome any helpful advice, experiences that others would like to share.

 

I w

[Erfolg]

Hmmmmm, should now be called the Guillows Thunderbolt.

 

Anyway, a few pictures

 

As can be seen, I have now filled all the gaps in the fuselage, FF style.

I really should have taken on board the notes on Mikes Flying models, and used 3/32" balsa insert. Instead I used 1/16". The extra thickness makes a difference in being able to leave that bit more stuck out, to sand back.

I cannot say I am a fan of this method, it would have been easier, quicker, to have modified the first Bulkhead, to reduce by 1/16" all round. Then to have planked with a 3" wide, 1/16" sheet, Pre formed around a former and stuck directly onto the ribs. Accepting the rest of the body would be 1/8" bigger than intended.

The next part of the process is to prepare for Glass cloth, WBV finish.

[Erfolg]

Should mention the weight has gone up to 64 gram, about 2.5 oz.

[Erfolg]

I have now glass sheaved the body. Although decorating most of the day, the job was done in an accumulative time of about 15-20 minutes. So time efficient, in my opinion.

 

This picture shows the cloth stuck on with WBV.

 

Two coats of WVP later. If I had used 3/32" balsa, the finish would have been far better. Sometimes you can try to hard to save weight.

 

 

The finished weight of the body is 81 grams. So about 17 grams from the finishing media. Interestingly the balsa infill is about 34 grams, far more significant.

 

Although the overall weight has doubled from the stick basic frame, as a technique I do believe it is warranted in both a massive increase in stiffness, and hopefully a bit more robust and resistant to minor damage that particularly tissue is susceptible to. In the case of film, it adds very little to the structural integrity.

 

I will be busy over the next few days, so it will be next week before I can start on the wing.

 

 

[Shane Sunday]

Wow you are really getting on with this build! I'm still in the planking phaze of the build. Looking at this I might have to get my finger out. Can I ask what weight cloth you used? I have poly C Which I reckon is like your WVP but would consider laminating resin. Keep up the good work. I'm going to get mine now as the hose is finally quiet.

 

Cheers

[Stephen Jones]

Hi Erfolg ,

 

Hmmm.... It seems as though you have added a lot of un-necessary weight to the fuselage from 30 Grams to 80 Grams .

Mine came out at 306 Grams AUW and the brown paper i added improved its overall strength , my model has hit the ground on a few occasions and came to no real harm .

 

Good Luck .

[Erfolg]

Hi Steven

 

You could be correct, time will tell.

 

You need to recognise that the 30g was the dare airframe, which was in my opinion inadequate in torsional strength. Although a believer in light models, from observation the FF type models do not do well in all weather flying. Although bouncing, they do seem to break disconcertingly. The successful open frame work RC models in the club, use far bigger sections than would be found on the same size FF model.

 

The skinning with balsa has added about 30 grams. The resulting structure is extremely rigid structurally.

 

Although 17g is the covering, it could be argued that Solar film would have provided a lighter finish.

 

For me this is as much is about a learning process, to put into own designs, particularly as I am becoming a lover of foam models. To some extent I am not sure that Balsa models is the best currently available material for whole model constructions.

 

When finished a better understanding of the appropriateness of the execution of this model can be formed. My objective is a pretty much all weather model, not just a fair weather model.

[Stephen Jones]

Hi Erfolg ,

 

I understand your concerns , but a heavy model will break far more on a heavy landing than a light model where its energy will be absorbed by long grass . Also a heavy model will need a bigger motor and battery adding more weight to a point where it wont fly .

 

Brown paper is also good on foam when used with Pva glue or Poly C .

 

You could always make it a good static model . As i was going to do with my p51 but as the method i used proved to be light and strong , i continued to make it RC .

 

 

Good Luck

and keep us posted .

 

 

 

[Erfolg]

Stephen

 

The trouble is I have seen a number of it will bounce FF type models disintegrate on the first heavy landing, when converted to RC. What kills them is the high concentrated loads arising from the Lipo, servos and the inertial effects from the motor.

 

I am aiming for the type of structural strength of the West Wings Toucan.

 

The one thing I do know, is RC models have to be a little stronger than FF, distributing these forces. Not the flying tanks, beloved by many RC scale modellers of the 70's. Yet stronger than FF. It is a balance.

 

I did see one stick and glue model where the modeller congratulated himself on how little superficial damage the model had incurred, other than all the RC bits rattling around inside. It then turned out the the damage to the sticks was so extensive that the model was seen as total scrap.

 

To a larger extent, that is why I have come to recognise the benefits of Blue and EPP models, they are light, they do bounce and the forces are absorbed by the foam, deforming etc. I have increasingly blended ply, balsa, blue foam with glass and WBV, which can produce light and very durable, and damage impact resistant models.

 

Above all they must fly on a typical UK flying day, not restricted to a light to none existent wind day.

 

[Shane Sunday]

I agree. With the both of you. On one hand I want the model strong. On the other I want it too be light enough to run off a 2 cell lipo. For this reason I have chosen to plank particular regions to strengthen as well as to adhere the solar film to. The 2 cell thing is why I have gone off glass cloth and resin. At the moment I am wrestling with the bell cranks. I've got the idea sorted. I have made a cranck from balsa and plastic card. The balsa is there to provide girth.

here are a couple of pics

I've lightened the tail feathers. That there is one handy tool for making holes of varying sizes.

Here we see number 1 rib duplicated to sandwich the servo

the ailerons were a bit fiddly

and the whole wing.

[Shane Sunday]

and just a couple more

[Erfolg]

Shane

 

It is looking good.

 

I will be using a 3s Lipo. The reason being that the motor I intend using CF 2812 is pretty gutless on a 2s, yet a little powerhouse on 3s.

 

I tend to agree with you Shane, in that there is no absolutely right way.

 

It is apparent that the issues of FF or CL models differ from RC models. It is almost universal that even FF models, in this era have the nose area re-enforced as your model. There is an issue that was not significant for FF, and that is of forces and inertia effects from RC equipment that beneficially require these forces dissipated into the structure to reduce stress levels.

 

I was discussing with a very well known, successful, FF competition modeller and semi professional journalist, why FF models are, or were built as they are. The comment about the wings, was that the multi stringer approach was purely to support the tissue, without undue sagging. With FF, the flight loads are light, as the structure is nearly always minimal. With respect to the conversion of FF models to CL, he observed, that this was not always done well, with bell cranks pulling loose, and some fly always due to using twine of insufficient strength.

 

On the basis of current norms for RC models, I will be building the wings on my model on more conventional lines.

[Shane Sunday]

I will be useing the Emax 2822 on a 2 cell lipo with a 10x6 prop. They say it will produce 18 ounces of thrust at 15 watts. So keep her light!!!!!! We shall see tho.

[Erfolg]

Shane

 

I have a number of CF 2822 motors in models,

 

 

the only one with a picture is above.

 

Recently a club member tried one as a 480 replacement on a Zaggi type. It would not fly.

 

I am not convinced that either CF 2822 or CF 2812 produces anything like that thrust on, particularly 2s. Even though I think they are a fantastic little motor.

 

I have now made the standard tail end assemblies, which have been sheaved in 1/32" balsa, again i hope to cover with glass cloth.

 

Complete with pilot.

I have added some re-enforcements for the hinges and clevis etc.

 

As yet I have not measured the weight of the tail feather's, although I suspect that the wire joiner adds more weight than is desirable. I do have some CF rod, which could have been used to advantage. The group weighs 27g.

At a recent club meeting that there was a kit, which was thought to be Balsa USA, which used preformed balsa shells, using a double lamination of something slightly less than 1/32" to form a shell of just +1/32", which was then stuck to a skeletal structure. They were designed apparently to use a 0.049 Cox. I was told they flew well.

 

 

 

Edited By Erfolg on 09/11/2011 10:59:50

Edited By Erfolg on 09/11/2011 11:00:24

[Erfolg]

I am anticipating a lambast from Shane, more unneeded weight.

 

I have started on the wings. I have modified the build, to both reflect the RC Groups build and to bring into line with modern RC general Practice.

 

 

I have added two spuce spars and am sheeting the wings .

 

I have used the supplied ribs and LE, the rest comes out of my stock.

 

The out line is the alternative model "N" outline, shown on one half the wing drawing. I have also washed out the tips. For one reason only, that I have seen a similar sized Wildcat, having issues when looping and landing. In the case of loos, squirreling out near the top of the loop, and when landing, needing to land very, very fast to avoid a vicious tip stall. The plus side of the approach, was that the model was flown in all weather. Not a fair weather model, accruing rips and tears in the tissue covering from stubble and other misadventures.

 

Of course the real issue will be what the fished weight will be.

 

My biggest concern, at present, is how to install the Servos, which will be 5g type.

[Stephen Jones]

Hi Erfolg ,

 

The wing servo ,

 

1 . One 9grm servo mounted in the centre using bell cranks

2. One 9grm servo mounted in the centre using snakes

3. Each wing having its own 5grm servo .

 

The choice is yours

 

[Shane Sunday]

Hahahaahahahaha. Well then I don't need to say anything. I'm sure you've more experience than me and therefore know why you're doing it. Will you sheet the top? I think I'm looking at the open top could be wrong. I've added wing tapes so I can iron on solarfilm. So I've added weight as well. If I weren't worried about weight I'd put micro servos in the wing. I am using bell cranks tho. What size battery you going to use? I'll post some more pix tomoro. Gonna redo the vert stab and cover the fuse.

 

Keep er lit!

[Erfolg]

Hi Stephen

 

The decision was made some time back, all my installations for ailerons are wing mounted close located push rods.

 

I was how to install them that is causing me some quandaries.

 

I suspect Shane we have different philospes. Stick models work well, with FF models taht do lazy circles at the stall, where you just hope the arival is not to big an event.

 

I have seen two and built one stick FF models as RC models. It was quite obvious that the model I choose a VC Tomboy, although a fine FF model, was useless as a RC model, particularly when the wind blew. In the first iteration, the Lipo destroyed the front end in a hardish landing, that sevos attachments were suspect, and the dihedral far to high for RC. I did modify my model in many ways, until it became an all weather RC model. Perhaps more significantly I have seen two tissue and stick models, essentially become a bag of bits from modest landings. There owners, saying, it should have bounced, why are all the front stringers wrecked.

 

I also believe in a light structure. In some respects foam models provide the answer. Any applied point loads, or evenly distributed loads are best dissipated by multiple pathways. Foam does this both at surface and internally (tri axial stress distribution) levels. The monocope that I try to construct, is not as effective in stress distribution as the foam, the stress paths all being two axis, surface stress. In principal it is a better solution than stick structures. The issue is that of weight. On reflection, 1/32" balsa shells stuck onto the sticks would have been a better solution. Any increase in weight, would result in a far stronger structure. I would suspect that it could have been lighter than brown paper, using Poly C.

 

As I have stated all along, my models must fly in all weather, to be any good to me. They must take the rough and tumble of flying from a grass field.

 

That is why I use the tried and tested methods of contemporay home built models.

[Shane Sunday]

Hey I'm still very new at all of this so all the info I can get helps. It helps me decide what it is I can do to make my models better. The only experience I have with stick models was when I was 15 and built a mustang that was rubber powered. Lets put it this way... It was never able to fly. So when it comes to a philosophy I'm still building one.

 

What I am looking for is a model that I can throw out my back door and belly land on the grass on those calm as days. I haven't had any opportunity to build anything this past week or so. Maybe get back at it next week.

Edited By Shane Sunday on 19/11/2011 10:25:32

[Erfolg]

Most of us are new to modelling to a degree. In my case I have been modelling again for about 7 years.

 

From general experience I do believe there is no one right way. My life in industry first highlighted the tendency to adopt, our way is right, there practices are poor. Ignoring any differences in circumstance or if the same end is achieved at a practical level it does not matter. Although sometimes one methodology is adopted as a part of a QA scheme. So I believe that the stick model works well in certain circumstances, I also believe that other methods also have there place, dependent on what is wanted.

 

A typical sort of situation is two models which I have. In many respects they are dimensionally very similar.

 

The first model is a Depron, flat plate winged park flyer/indoor model. The flat plate works well at one airspeed, at others it can be very poor. This is particularly obvious when flying out doors in wind. There are some very percular dives , stalls in wind. At one time I thought I had a Rx issue, when changed the issues persted.

 

The second model is similar, other than a built up wing (I beam and stick wing), the body light ply and carbon boom. This model has a far greater speed range, no handling issues what so ever.

 

The first model has a very slow flying speed. In no wind the stall is predictable, by wing rocking, with any wind, the bouncing about hides the onset of the stall, which is then sudden. The angle of attack can be surprisingly high,in still air, I suspect due to propeller wash. It is apparently not as high in wind, if not in prop hanging wash.

 

The second model has a very wide speed range. From an efficiency point of view higher wind speeds or speed seem to improve efficiency of the wing. The characteristics being well suited for outside roles.

 

What I am trying to say, what you expect from a model and the environment it will operate has quite an impact on the appropriate solutions.

 

To be honest I do not expect to much from my model. Preferring bigger wing chords, which tends towards bigger models.

 

There have been many successful conversions of FF models. Yet for many, they are flown in a similar way to FF models, that is in good weather, with little wind. They are seeking a model which has a modest performance envelope. In my case i believe I will have to accept a higher flying speed, to get the control I want in all weathers, not just calm evenings or the occasional perfect days.

 

I am prepared to accept failure, in my goals. But better to try and fail, than have just another kit on top of the wardrobe.

[Shane Sunday]

How goes the build? I've had zero chance to get onto the corsair. I'm still thinkin of the electronics and the placement. Would realy like to see how your getting on. t least someone is building.....

[Erfolg]

Hi Shane

 

I guess things have not moved on much.

 

I have just installed the aileron servos and servo extension leads.

 

I will be sheeting the top surfaces next.

 

I do not expect to make much progress in the next few days, as I will be baby sitting, whilst my daughter no.1 and son-in-law house hunt. Plus I am hoping on Sunday i will be able to fly a model or two.

 

Like you i will next be considering the equipment placement. I will temporarily assemble the bits and see where the CG comes out. I am a little concerned that the tail assembly is heavier proportionally than I would have expected. I can only assume that PVA weighs a lot more than a Cyno assembly. Particularly when it is considered that the sheeting is 1/32".

 

I am not really anticipating any major issues, but I have often been surprised, or is that just plain wrong.

 

 

[Erfolg]

I am coming to the completion of the wing

 

It uses as previously stated the wing ribs and LE. Spruce spars and standard TE.

 

 

 

The hardest part has been getting the washout into the ailerons.

I have mixed feelings with respect to washout, the kit has no washout. I have seen some (small) models of Spitfires without washout the have been very prone to tip stalling unless always kept moving. The most spectacular, was one that was traveling fast, coming into land, when slowed just prior to touchdown, tip stalled and disintegrated in a whirling spectacle.

Yet I have seen some plans of similar plan forms, particularly a Hawker Tempest 5 with none what so ever as designed.

The unfinished wing comes in so far at 142g. Perhaps 1/32 sheeting could have been used to advantage. Then I would suspect it would be susceptible to both handling and field damage.