Lockheed Vega

[Lindsay Todd]

Well more than one project going on of late and this one has been in the planning for some time but in need of a little break from the Blenheim i decided to crack on. The drawings have actually been complete for a couple of months so a quick call to Slec provided a rapid turn around of super quality parts that arrived quickly and allowed some really rapid progress over the last couple of weeks.

The little diecast and film Amelia have been useful inspiration, I intend to replica the red colour scheme of Amilia Earharts aircraft and as the blog goes on will fill in some background to the aircraft itself.

I'll start the blog construction notes off properley in a few days but for now here is a couple of shots as she stood before and after the weekends progress.

She stands at 57" wing span and has been designed around using my 3cell lipo packs and 300 watt 1100kv motor, not sure of a final weight but circa 3-3.5lb should be realistic I hope. Anyway hope this wets the appetite and will kick the build off properely soon. Linds

[GrahamC]

That looks good.... I do like a good build blog, so I'll be watching with interest!

Edited By GrahamC on 09/12/2013 07:45:11

[Dave Miller]

An excellent project, as indeed was the film.

[Peter Miller]

Very nice.

For years I have considered the fact that a kit manufacturer could make one GRP fuselage and one foam wing and make the whole rance of Lockheeds, just needs a variation in U/C and tail surfaces and some different wing fairing.

Thinks of it, The Vega, Orion, Sirius, Air Express and then float planes as well..

I look at the Wylam (or is it Nye) set of drawings and think about it. But then I am too lazy to do anything about it!

[Tony Bennett]

now that does look nice.

grrrrrrrrrrrrrrrrrrrrrr see what i mean about sanity warnings. cos i fancy this one as well.

[Biggles' Elder Brother - Moderator]

Amazing aeroplane the Vega - held a lot of distance and endurance records at one time. Nice start Linds

BEB

[Tim Hooper]

NIce one, Linds.

You don't mess about, do you?

tim

[Lindsay Todd]

I think we have much in common Tim

Thanks for all the comments, much appreciated, time to start of the build I guess starting with something nice and simple with the tail plane and elevators. The elevator is entirely made up from pieces of medium grade 6mm balsa cut into various widths to form leading edge, trailing edge and cross bracing. The only issue here is to make sure the grain always runs parallel to the span and that the joints are nice and tight. The only tricky bit to cut is the leading edge profile. The little fillets at the front are actually a bit of a problem later and we will need to trim one away when we slide the tail into the fuselage but leave it all intact for now.

The elevators are made up of laminates of 2mm medium balsa, a centre core the exact size and then 6mm wide strips glued top and bottom to increase the thickness to 6mm and simulate the ribs. We then add some 2mm ply to the centre region aft of the leading edge, again top and bottom to give support for the wire joiner and horn fixing. Finally the elevators are sanded from the rear of the leading edge strip to the trailing edge to feather the profile and a 45 chamfer given to the leading edge and job is basically done. simples.

The rudder and fin follow exactly the same mode of construction as the tail and elevators, again note the ply doublers added for the tail wheel wire and horn location to add strength. The fin will slot into the fuselage and sit down onto the surface of the tail. A couple of triangular fillets for strength and rounding off of the leading edge is all that's required.

So with some easy bits out the way its time to get started on the fuselage. I took advantage of Slec's cnc cutting service to provide me with a super set of parts, basically the fuselage formers, wing seats and ribs for the wings plus a few other items.

It certainly saves an awful lot of time, providing your drawings were correct to start with. I have to admit I have made a couple of amendments as I progressed, these have been addressed for future but I'll try to highlight them as I progress. Most were actually associated with the formers around the cockpit area as the shape was difficult to visualize initially so I went with an option that would allow me to 'figure it out' as I went along and it has so far proved to have been a sensible option and was in fact far less complex than I had first thought.

I don't own a building jig, but I have to admit it would be helpful sometimes. The fuselage is built around a series of formers supported by 6mm square longerons and a 6mm sheet wing seat so stays fairly flexible initially so some careful marking out and a little patience is required to keep checking all stays square.

To start however we need to laminate the fire wall former and former number 3. The firewall simply increases thickness and strength, former 3 will have part of the undercarriage fixed to it so it also needs some strengthening plus the front doubler also forms the cut out for the battery compartment that runs from former 3 through to the firewall. When dry a quick sand and we can start the fuselage assembly process.

Two longeron's run parallel the length of the fuselage from 6mm square balsa start by pinning these down over the plan from the firewall forward face and clearly mark the position of each former. When marked up remove and pin down a second set and repeat the process. The build starts by gluing former 3 and 4 square to these longeron's. A wing support is cut from 6mm balsa sheet and is glued flush to the front of former 3 and runs square back through a slot in former 4. Position and glue this in place ensuring the formers stay square, when dry we can now add the second set of longeron's to the opposite side of the fuselage making sure the former positions are aligned. When dry add the second 6mm wing seat between former 3 and 4 check for square and glue in place. When dry we can add former 5 which locates onto the rear of the wing seat and should be set square. Glue to the wing seat first and when dry the longeron's can be pulled into the former and also glued, tape and cyno is probably easiest for this.

Once this assembly is dry we have a bit more strength and subsequent aft formers 6,7,8 and 9 can be added one at a time aligning with the marks we made on the longeron's and check for square as we go. At this point we can also add the top centre longeron that extends flush to the front of former 5 and back to the rear face of former 9.

well I recon that's a good start for now. More soon. Linds

[kc]

A 57 inch span scale model with a chunky fuselage & radial cowl to weigh 3 to 3.5 pounds? Sounds as if Lindsay has got some pre production samples of the new helium filled balsa!
Normal builders would expect 4 to 4.5 pounds with lots of lead up front wouldn't they?

[Lindsay Todd]

Kc, I think at this stage it is fair to say the final weight of the model is unknown, I see no harm in having a goal to aim at as chunky means there is a lot of fresh air which last time I looked didn't weigh very much. We'll have to 'weight' (get it) and see who's closest when she is ready to fly. If it's 4.5lb that's still sounds pretty good to me. Linds

[kc]

The idea of a 57 inch scale model for 300watt and 3S seems a great idea. However I based my assumptions on the nearest model I have seen which is Peter Millers 57 inch Cessna C37 Airmaster ( Flying Scale Models Feb 2009)for .32 glow which PM said weighed 4 pound 12 ounces. The Cessna had sheet balsa tailplane & fin rather than built up. Even allowing for less vibration in electric and therefore less in the way of ply doublers fuel proofing etc 3.5 pounds seems optimistic. However one has to be optimistic and aim low (weight)
I hope you manage it and it becomes a pull out plan for RCME.

[Vecchio Austriaco]

looks good, looking forward to see it finished!

VA

[Colin Leighfield]

What a great choice Lindsay, a true all time classic. Hard to see how it can't fly anything but really well.

[Lindsay Todd]

Time for a further catch up

Repeating our process for the rear formers, the cockpit front panel and firewall can now be aligned with our marks and pulled together to meet up with the longeron's. The firewall sits parallel to former 3 and this is helpful to take measurements from to ensure it is sitting square as of course it dictates the thrust line and is therefore critical in the build so take your time making sure before gluing permanently in place.

The additional longeron's around the fuselage can now be added and glued, this adds significant stiffness to the structure and once they are all in place the fuselage is quite robust. Next job is to glue the 3mm balsa sheeting to the base and sides of the battery compartment that runs from the former 3 doubler through to the firewall. This has been sized against my own 3cell lipo packs 2500mah, there is a bit of slack but if you have different sized or larger packs now is a good time to open this area up a little if necessary to fit your own packs, just ensure you don't go so deep that you impact on the motor mount position central to the firewall.

Back to the rear of the fuselage and time to fit the lite-ply tail plane support and triangular brace, the support locates into a cut out in former 9 that fixes the position and the support sets the correct angle. The last former 10 is then glued onto the back of the support and a little triangular stock added for strength. The lower centre longeron is then flexed up and glued into former 10, I added a few cut slots to remove pressure on the bend and when in place added a few drops of cyno to fix.

more soon. Linds

[Richard Harris]

Linds,

An excellent choice!. I really do like the 1920's/30's aircraft . I am sure I read somewhere that the fuselage was moulded in two halves over a concrete plug?

I will be watching with great interest.

Rich

[Lindsay Todd]

Well very soon actually.

The fuselage shape at the rear of the wing seat has to conform to the fuselage shape so to do this, and it is a bit of a compromise from scale, but then this is very much sport scale so that's ok, we build up the inside face aft of former 4 with laminates of 6mm sheet , slowly reducing in length as we get towards the centre line rear of the open area that the wing sits on. Eventually what we are aiming for is a minimum 6mm land for the wing seat once we shave and sand the excess away.

The black line shows the shape and line we now need to trim and sand back too. I found this a relatively easy task with a razor plane and final sand to shape blending nicely with former 5.

A couple of more laminates and I will then also trim the inside edge to approx. 6-8mm thickness. I have kept all these laminates to the same depth and will use the underside as a fixing height later when I come to fix the wing bolt plate into position.

more updates soon. Linds

[Simon Chaddock]

Nice build.

The remarkable feature of the Vega was how the fuselage was made.

It had a normal former and stringer structure but the skin was added as a pre moulded half shell in one piece!

Each half shell was built up in a female concrete mould and before the glue set a rubber bladder was lowered in and air pressure used to force the complete skin accurately into shape.

It created an exact profile with a good surface finish but was expensive to do.

The De Havilland method using a thick self supporting ply/balsa/ply sandwich skin built over a male mould was probably more practical for mass production.

 

Edited By Simon Chaddock on 12/12/2013 13:47:00

[Erfolg]

I am not sure that the Lockheed system is any poorer than the Dehavilland method.

The Lockheed system is essentially the same as has been used for large GRP vessels (boats and yachts), then many glass/CF/Kevlar composite models are produced, in addition to some racing motor vehicle body components. Its advantage is that the accuracy and high surface finish are achieved of the moulds.

In the case of Lockheed, using concrete for the moulds, meant that they were extremely heavy and not easily moved.

I do like the idea of Peters for a manufacturer, in that for a relatively small outlay a whole range of scale models can be economically kitted.

As for the model under construction. Well I stand in awe, not having the skill or patience to build such a model.

It looks good now, I am certain it will look even better when constructed. Perhaps I am wrong there, as much of the craftsmanship will not be evident, particularly to the casual observer, on the other hand, the superb shape and of course the finish will compensate.

I increasingly see that electric propulsion has become ever more popular in the larger size models. I guess it is the ease of accommodating the drive train. Rather than have to juggle the cooling and exhaust requirements of IC engines. I am also guessing that the model can be built lighter, with all the benefits that come with weight reduction.

[kc]

It looks like there is only space for 1 wing bolt and yet there looks like only 1 dowel Would be strong enough for a light model but will it seat the wing firmly?

[Lindsay Todd]

1 wing bolt, 1 dowel, yes quite adequate for this design, of course you could always add more to yours if so desired. The wing seat is actually quite wide so well supported. I'm not planning any high G manoeuvres so no need to go for anything more on this design, however it will use a heavy weight nylon bolt just in case.

Very interesting re construction of the full size, lots in common with composite technology today. Linds

[Lindsay Todd]

Another build update and its time to add some sheeting to the fuselage. partly because of the shape and partly because I had some shorter lengths I chose to sheet the fuselage in panels of 2mm soft to medium balsa. Starting from a midpoint on the lower of the fuselage parallel longeron's and using a centre line through former 3 and former 5 up to the wing seat position and centre line through the upper longeron. Its a little slow and each panel was dampened to help with the curvature before being glued, pinned and clamped. To start with I just covered the upper surface areas leaving the underside open to assist with fitting the control snakes later. In fairness you could fit these before sheeting, I had to wait to get to the model shop so started on the sheeting first.

Once both side were in place it was also a good time to fit the undercarriage blocks, this is from hardwood block and mounted in four places around the fuselage. The first two are mounted to the rear of former 3 and front of former 4 flush to the lower edge centre of the formers. The centre longeron needs to be cut away and then refitted between the blocks, additional strengthening to the blocks is by triangular section balsa above and ply braces either side.

The above photo shows a real clanger on my part, gluing the upper mounting blocks too low! they should sit between the two longerons and against the rear of former 3. These blocks are pre drilled on centre with a 3mm hole as the wire legs will locate through these blocks, again additional bracing by way of triangular balsa around the inside.

Next job is to fix the elevator snake, holes are pre drilled in the formers so this just needs to be positioned so that it extends clear of the tail plane support on the underside.

The rudder will be closed loop but will run through plastic tubes so also a good time to fix these in place

Plenty of space within the fuselage, and when the snakes are fixed we can continue with the sheeting around the remainder of the fuelage

A little care required around the snake exit points and worth thinking about where the horn will be to set a reasonable depth. Cut a whole to clear the snake and when dry can be cut and sanded to the fuselage profile.

that's it for now, more soon. Linds

[Bob Cotsford]

Lovely model Lindsay, just the job for a nice oily 52 four stroke, and wouldn't it sound nice

[Lindsay Todd]

Thanks Bob, indeed it would, alas this one is destined for electric.

Time to crack on with the updates and the next job is completing the tail section and creating the slots for the tail plane and fin.

A little bit of measuring required first to set the position of the tail square to the fuselage, this sits directly onto the ply support and sits square to the front of F9, once happy a couple on pins to secure, then position the fin and mark its position at the front and rear. We now need to remove the tail plane and add a couple of strips of scrap 6mm balsa plus some cereal card for tolerance. The fin is then relocated back into position.

With the fin set square we can now add soft block in strips between the edge of the fin and glued to former 9 and former 10, do not allow the glue to fix the fin at this stage.

Once the first couple of blocks are in place the fin can be removed and replaced with a bit of scrap. We also take the opportunity to guide the closed loop snakes with a laminate thickness with a slot cut through.

With the remaining laminates of soft balsa in place it can be sand to shape of former 10. We can now add the tail block, again made from soft balsa and simply glued to the rear of former 10.

At this point we need to make a start on the wing as we have some centre section angles that define the cockpit area so I guess that's for next time. Linds

 

Edited By Lindsay Todd on 14/12/2013 23:39:26

[Lindsay Todd]

Well just a final check of the rear of the fuselage with the fin and rudder plus tail plane I situ and all looking ok so its time to make a start on the main wing.

The wing having a flat top surface with the taper on the underside means that we build the wing upside down and if you have the space could be built full span. I didn't so built the wing up in two panels and then joined the panels. as usual start with cutting out the ribs. Note the extended tabs that allows the wing to sit flat upside down on the building board.

Construction starts with laminating up the spars, these are made from medium to hard 6mm square balsa and the spar is double thickness extending out to the 5th rib from the centre line of the wing. Pin the spar flush to the centre line on the plan and then glue the 6mm hard balsa spar brace to the rear making sure it is upside down, ie angle upwards.

We can then position and glue in the place the vertical ribs, this is effectively rib number 2 onwards as rib number 1 is in two halves and will be glued at an angle matching the spar brace.

We can now add the rear of rib 1, this is glued to the inside face of the balsa spar brace up against the rear of the spar. We can then add the top spar which is a repeat of the lower and this can be glued in situ and also add the upper rear spar from medium 6mm square balsa. The leading edge can also be added; this is from 6mm medium balsa cut to length and width and glued to the front face of the ribs. Note this extends passed the position of the first rib but does not need to extend to the centre line as we will cut this back to clear the cockpit area.

When dry we can remove and repeat the process to create the opposite panel; when ready we can bring the two panels together at the centre line and glue to the rear balsa spar brace. We can now slot in place the two front rib number 1 parts. these are set and angle defined by the ply dowel plate so use this to set the position before glue the ribs to the spar, when dry position and glue the dowel plate into position. This controls the position of the wing to the fuselage so ensure that it sits square. When dry we can also add the front ply spar brace (identical to the dowel plate). not shown in the above picture as I added later, but now is the time to fix it in place really.

Final job for the moment was to add the 6mm trailing edge to the aileron cut outs, this is simply sheet cut to length and depth. I also added some 3mm triangular braces and glued between ribs and leading / trailing edges for some extra strength. Next job will be to get some sheeting onto the wing. more updates soon. Linds

[Simon Chaddock]

Linds

A nice build!

I guess from the past tense used in your text the Vega is now finished.