Esher & District Model Flying Club

President: D.A.E. Smith B.Sc. (Eng.), C Eng., F.I. MECH. E.

Vice Presidents: M. Charles Esq. J.S. Barker Esq.

COMMITTEE

April 2000

Dates for Your Diary

Editors Notes

My wife's church, Holy Cross C of E in Motspur Park, have each undertaken to raise £100 this year to help build a school in Lesotho.

A railway modeller - who not only has a model railway in his garden, but a complete, working ex British Rail signal box - has decided to hold a small model show on Saturday 25^th November and I have volunteered the club to put on a static display. So if you (still!) have a model you would like to show off by this November, please let me know, and if its too wet and windy to fly that day, you know where you can go (in the nicest possible way!). I guess it will be like a miniature Model Engineering Exhibition but with no involvement by Nexus it might be quite good!

Chairman's Notes

First I would like to thank Keith for the talks he gave at the club meetings, one on transmitters and receivers and one on electric's for planes.

These were well received by the members and the handouts on both subjects will be very useful to keep. (Editor's note, if you missed either talk and would like a copy of the handouts I still have a few copies left so please see me).

The main season is almost upon us now, so keep a watch on the club board for outings to the best events of the year.

Our own show on the 18^th June needs help for mowing the strip and sorting out where it will be sited. This will be done on the Thursday and Friday before the show.

Please contact me if you can help.

I would like to remind members that if they have not had their planes checked for noise levels they will not be allowed to fly until checked. Tony F.

Secretary’s Notes:

Your committee meets 3 or 4 times a year, and Dave made the point that we do not distribute minutes so I will send out notes in future.

We met on 20^th April and here is what it was about:

1. Reigate Field – We hope to return 10th June, so the Winter Field will close then. (We cannot use it all year)
2. Membership stands at 69. This is less than I thought, so please check you are on the database. I will bring it to club meetings and to the field, and you can have a copy.
3. Club Show on 29^th April – The West Surrey Centre Caravan Club Millennium Rally. The field will be closed for general flying, but B Cert. holders welcome to fly, and all club support welcome. If you have a nice model you would like one of us to fly, let me know. Dave will do the PA.
4. Club Show at Brooklands, Sunday 18^th June. Tony has already booked 25 flyers and we agreed the flying programme. There will be a mixture of fun comps, guest slots and sport slots for club flyers. So get that B-cert and YOU can fly. There will be setting up and grass cutting on Friday 16^th – let Tony Fuller know if you can help then – and final set up, practice and barbecue on the Saturday. All helpers can fly on the Saturday afternoon once set up is complete and we will have the buddy boxes. The club flying field will of course be closed that day. Please support the club that weekend if you can – we will be collecting helper's names.
5. The Club Barbecue will be held again, at Ewell. Alan will be selling tickets.
6. Club outing to model show at Woodsprings, Bristol, on Sunday 2^nd July. Those who went last year raved about it – so this year we are ALL going! We hope to have enough for a coach. I shall invite the Addlestone club to help fill it. Bring the family.

Proposed outings

Woodspring on 2nd July Yatton - North Somerset. Full size and models, A coach will be arranged providing enough people want to go. Please let Alan know.

Our show

As last year models will be checked before they can be flown.

We still need volunteers to help set up on Saturday and we also need people who can assist with mowing and hole filling on Friday. Please contact Tony Fuller if you can help. See Jeff Cosford to see what jobs need doing.

Jeff

A Better Firewall.

If you go to the Sandown Show this year, make straight for the helicopter stands.

"But I'm not interested in helicopters", you say.

No, but at least one of the manufacturers regularly sells a bag of carbon fibre off-cuts for £2-£3. This usually consists of various short lengths of ¼" tube plus odd shaped pieces of ¹/₁₆" to ¹/₈" sheet. The tube is excellent for such jobs as high tech unbreakable wing dowels, rudderposts, etc.

The sheet also has many uses, but the best I have found is to replace the normal ply firewall in any aircraft you are building.

A carbon fibre firewall is:

• Lighter.
• Stronger.
• Totally fuel proof.
• Virtually indestructible.
• Can be glued with Cyano or Epoxy.
• For about 20p can be turned into a superb quiet mount.

Carbon fibre cuts and sands like plywood, unfortunately the fibres are very abrasive so you will be able to cut about 18" before a junior hacksaw blade's teeth are completely worn away!

Making a Quiet Mount

For any aircraft where a conventional moulded engine mount is designed to bolt to the firewall, use the supplied ply firewall as a template and cut out a replacement in carbon fibre.

Obtain suitable bolts for the engine mount and get rubber grommets that fit over these. Grommets can be obtained, for a few pence each, from car spares shops: XL Motor Spares 280 Burlington Road, New Malden, for example, has them in dozens of sizes.

Drill holes through the carbon fibre in the correct locations for your engine mount, wide enough to allow the rubber grommets to be fitted - see Figure 1.

Figure 1 - A Carbon Fibre Quiet Mount

Fit the bolts with the heads on the inside of the aircraft. If the heads can be reached OK in the finished aircraft use Allen headed bolts. If they cannot, use flat head bolts and solder (or braze) a length of piano wire across two bolts to stop them turning. This is most easily done by using the engine mount as a jig. Fit the bolts direct to the mount with a nut either side as shown in Figure 2. Leave as much of the bolt proud as possible to prevent heating the mount when soldering.

With the rubber grommets and bolts (if necessary) fitted, the firewall can be glued to the airframe. Remember that the carbon fibre is much thinner than the original ply firewall, you will probably need to include packing behind the firewall to ensure that its front face is were the plan expects it to be. You should include triangular balsa (½" for a .40 engine) behind the firewall to distribute the load and increase the glued area if possible.

The engine mount can be bolted on using nylock nuts at your leisure. Do not over tighten the nuts, they should be tightened just enough to remove any play in the engine mount with as little compression of the rubber as possible. Using this system dramatically reduces engine noise through the airframe, my OS15 powered fun flier achieves 76dB at 7 metres.

The system can also be used with engine bearers if they are set up wide enough to fit the engine on a mounting plate. Make the mounting plate from carbon fibre and bolt it to the bearers with rubber grommets in the mounting holes. Allowance will be needed for the engine being about ³/₁₆" higher than if mounted direct to the bearers.

Keith

Plans Database

Jeff has started to compile a list of plans held by members that are available for others to use.

While mentioning plans, there are now a number of sites on the Internet where plans can be downloaded in 'CAD' (that’s "Computer Aided Design") format. I have just obtained a plan from:

http://www.ezonemag.com/ of a CAP 21 type electric plane called the "Ampmaster".

There is also a site with dozens of RC plane plans: http://www.starcadplans.com/

The downside, having found some suitable CAD software to use, is printing the plans out in A4 sized bits and sticking them together. However I found that this was quite easy and was more than outweighed by being able to print out as many copies of ribs and formers as you like and sticking them straight to the wood to cut around. Keith

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