Vintage Model Co Se5a

Thanks I hope it clears, it came in the kit so it had better do so!!
I am at a quandry, I was warned that ballast would be needed, and I am sure those blessed paper decals ot the back have something to do with it, but 7.4g of lead is needed in the nose
Now the opening in the bulkhead is too small to do anything through there, my cunning plan is to make a round hole in the bulkhead, and glue a short length of styrene tube flush with the bulkhead. Then little beads of lead can be added/removed at will. I am thinking sellotape over the bulkhead to seal the tube. Any thoughts???





Cheers
Danny

I am setting it as indicated on the plan, so it should be about right?
I think scale free flight and C/L are odd they tend to be more nose heavy, it is R/C that have a more rearwards c of g??
Cheers
Danny

There isn't enough meat at the bottom of the bulkhead so unless anybody can see a reason why not, I am going to insert this little bucket of lead in a hole indicated by the blue line. I am thinking that I will use epoxy to bond the lead together to a weight of 5g, then that will leave a further 2.4g that will be loose, and can be added to or removed as needed. The epoxied 5g will then not be trying to burst out of the tape on an abrupt arrival!

A long time since I tried working out C/G positions. I'll have to dig out the books but I think the position is largely relative to nose moments, Incidence angles ,and weight distribution. Hence your SE 5 needing nose ballast in lieu of an engine . A motorised model might need tail ballast. Andy would be the man to advise you on this properly . Your idea seems a good one to me .

Hi Septic,

For what it's worth, here is my two-penn'erth!

1. The hole in the nose is far too small, you'll never get a winding tube in there. You may not even get a wound motor. However, it is what it is, so leave it like that for the short term.

2. Lead: Trim the model first using modelling clay/bluetack/whatever. When you have the correct C of G for flight, then add the lead in a more permanent way. Your idea of a box is good, but I would put it low rather than high - keep the centre of mass as low as possible.

3. C of G: Klippy is right about rearward c off gs for duration models with ENORMOUS tailplanes. Scale models have small tailplanes, so they need a more forward C of G.

4. The prop does look a little large. if it inhibits an ROG, just shave a bit off each blade until the ROG works.

That's about all for now, I might add a bit tomorrow after I've thought about it a bit.

The further away from the CofG you can get the ballast the less you need.
So once you have the required CofG position from testing using Blu tack or what ever as Andy suggests then I would achieve that CofG position by carefully hollowing out the rear face of the nose block and gluing in thin sheet of lead.

Quorneng wrote: The further away from the CofG you can get the ballast the less you need.
So once you have the required CofG position from testing using Blu tack or what ever as Andy suggests then I would achieve that CofG position by carefully hollowing out the rear face of the nose block and gluing in thin sheet of lead.

Q's suggestion is good in principle, but in practice, it makes the nose block heavy, which in turn, can cause it to fall out as the model lands, losing landing marks in the process. So, for a competition model such as this one, I'd get the final weights as far forward as possible, but still within the body of the model.

Thanks for all the suggestions chaps. Andy had already warned me about adding weight to the nose block causing it to fall out. He also warned against magnets to hold the block as shimming the thrust angles would stop the magnets working. I wanted to use the largest diameter piece of tube so that the lead was as far forward as possible. The model needs 7.4g of weight that is a big lump of plasticine, and would be difficult to attach as the nose is all tissue. 5g glued on as I have shown will still need more weight and this can be achieved by adding shot to my tube or plasticine. There is insufficient room to open the bulkhead under the prop shaft unfortunately as that would add weight under the thrust line which is good. But over the thrust line seems to be the lesser of all evils. The prop has 5/16 clearance when tail raised.....
Cheers
Danny

Could you slip sheet lead through a slot coated in glue and stick it inside the bulkhead ? I don't know how practical it would be to do but just a thought as you would have to make up or find a tool to slip in and press it into place.

I may be wrong but it does look like you have 'extended' the nose plug that fits into the bulkhead?
There is a danger that it might actually damage the bulkhead if the nose block had to 'give' much on landing.

Please be gentle with me , this is my first post on here and I'm a newbie , I've just bought this model and I noticed in Danny's photos show parts pinned to board but the advice in the booklet says "never push pins through the balsa parts"

Hi Mark
We DO try to be gentle with folks on here, and in the main we achieve that aim. However, may i request that you stick a post in the "Introduce Yourself" thread, giving us a few details of roughly where you live, and age etc
I will not answer your question, as we have experts on here who can give you far better advise on building than I can. I prefer the flying side of the hobby .

Garry

Hi Bennie and welcome
You might see me put a pin through large pieces of balsa, but never through thin or structural pieces like spars, stringers etc. The pins are either side of the wood at an angle, often crossing above the part I am trying to pin down. A pin through a structural part will weaken it greatly so I aim to avoid this.
I look forward to seeing how you get on
Cheers
Danny