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Member postings for PeterF

Here is a list of all the postings PeterF has made in our forums. Click on a thread name to jump to the thread.

Thread: The Gov't, CAA, BMFA & UAV legislation thread
06/11/2019 17:35:34
Posted by Nigel R on 06/11/2019 17:10:20:

Well I decided to just do the CAA site test.

Total time, 5 minutes. It is not difficult at all, especially as you can keep the answers handy and search through them.

I shall now be a good boy and stick my magic number on my toys, and look forward to enjoying all the positive benefits that registration can bring me.

Stick the Operator Registration number on, not the pilot flyer ID that came from doing the test.

Thread: New 78" Vulcan for twin 90mm DF
04/11/2019 17:20:23

Last few days have been spent wrangling the fans and thrust tubes into place but they are now in there and work OK. Thrust tubes from Mylar from a craft shop used for stencils and Gorilla tape. I made the thrust tubes parallel because the change in shape to an obround at the outlet will cut down the cross sectional area close to the FSA of the fan. For a plane like the Vulcan where speed is not of the essence there is no point in reducing the thrust tube outlet to smaller than the FSA to increase the efflux velocity. In fact the obround holes in the outlet former were larger than the thrust tube, so I put some infill strips of balsa to close the gaps up and stop the thrust tube deforming at high throttle.

Fans and thrust tubes installeddsc08467.jpg

Fans and thrust tubes installeddsc08456.jpg

Outlet former larger than thrust tubedsc08449.jpg

Outlet former with balsa infill to match thrust tubedsc08452.jpg

Balsa sheet to control the obround shape of the thrust tube at the outletdsc08453.jpg

Thread: The Gov't, CAA, BMFA & UAV legislation thread
03/11/2019 17:56:21
Posted by Michael Adams 3 on 03/11/2019 12:48:58:

Hi, it is alright for pilots who live near to a club, we are two who live right into the country side miles from any club, or airport.

it takes more time to travel to & from the field some times than to fly, we are country members of the BMFA. So how would any one come to us to train us we are really competent with the safety rules, and do not fly near buildings or over our car park area, also only one of us has an A certificate, so how can the other pass with out proper training from a club member present ?

Mike.

As Steve said, take the simple CAA test or wait for the BMFA to role out their new competency test which will br along the lines of the CAA one and do that.

Thread: New 78" Vulcan for twin 90mm DF
02/11/2019 23:44:47

Greg, thanks and checked it out, very useful as more detail than on here. I like the idea of the top access hatches, I'll have to think about that. I have had one plane with the battery access underneath and it was a real pain and in this case with 4 XT90 connectors to make each time!!!!.

I have completed sheeting the top of the fuselage section to the fan mounts and built up the nose section. This is relatively straightforward as it uses interlocking pieces, but being light ply, you need to make sure everything is straight before gluing. Not quite ready to glue the nose onto the fuselage yet, but it was a quick win in terms of progress.

Top sheeting completed to fansdsc08428.jpg

Top sheeting completed to fansdsc08434.jpg

Nose section under construction and checking for straightnessdsc08376.jpg

Test attachment of nosedsc08435.jpg

Thread: Am I getting to complicated?
01/11/2019 15:40:53

Well that helps sort things out somewhat better.

The motor may be being over driven with too large a prop. One guidance is that the continuous power rating of a motor is about 3 to 4 Watt per gram so this would give a power rating for this 378g motor of about 1200 to 1500W. The HobbyKing 1750W and 70A are maximum ratings.

Another factor that shows a motor is heavily loaded is the achieved Kv under load, which is coming out at 7800/23.4 = 333, which is 78% of the rated unloaded Kv. Such a reduction in loaded Kv is an indication that the propeller load is heavier than desired, on all of my electric planes that are well set up with suitable props I see a loaded Kv of 85-90% of the unloaded Kv.

The final arbiter in these things is always cooling and the temperature achieved by the motor during flight. eCalc is certainly suggesting that with medium cooling the motor is getting into the warning region. If the motor is uncowled and hanging out in the breeze then it may not be too much of an issue. Someone else may be able to comment on this.

Thread: New 78" Vulcan for twin 90mm DF
30/10/2019 17:37:50

Posted by Martin McIntosh on 27/10/2019 19:40:31:

Sounds just like the SLEC cut cnc pack for a 72" Spit. I built. Whatever the ribs were made from it was not what I would call lite ply.

Martin,

You are right, the outer sheet of the lite ply is something with a very porous open grain structure, it really soaks up the glue leaving little hanging around the joints. Whenever I have bought a kit with lite ply before, the outer layers of the ply have been similar to normal ply, with a light softer wood in the core. Quite odd, but onward with the build.

I have got most of the ribs and spars together to make the frame for the fuselage section including the fan mounts. Once this lost is together it creates a relatively rigid box structure. Whilst gluing all the spars and formers into the ribs, I have used some carbon fibre rod to keep the ribs straight.

A couple of things on the plan if you are reading this before building one of your own. The plywood spars FS1 need to be notched at W2 as W1, W2 and W3 are not uniformly sloped at this location, it is not noted on the plan. Secondly, the rear tabs on the ribs WS1 were a bit long and they fouled FS2 / FS2A, sand them down and it all goes together. The final thing, the front 9mm x 9mm spars should be hard balsa, the plan does not state so I started building them in obechi and then found that there was not enough obechi in the wood pack to complete them, so off the the LMS to buy 2 more strips to complete the spars and replace the wood I had inadvertently used. Oh, well, check next time the plan is not specific on a point before applying the saw and glue.

Fuselage section ready for sheetingdsc08382.jpg

Carbon fibre tube to keep the central spine straightdsc08379.jpg

Notch on FS1dsc08361.jpg

Rear tab of WS1dsc08364.jpg

Thread: The Gov't, CAA, BMFA & UAV legislation thread
30/10/2019 17:13:32
Posted by Ron Gray on 30/10/2019 16:07:35:

The BMFA were supposed to get some answers regarding the insurance angle and registration / non registration, by the end of last week, have I missed seeing it?

No, nothing new has come out, check the BMFA News page (link here). If you sign up for BMFA News email alerts then you will not miss anything.

30/10/2019 17:12:12
Posted by Nigel Heather on 30/10/2019 15:47:20:

So my concern at the moment is when are the 'idiot' tests going to be available. My club AGM is usually in mid-November and they take combined club and BMFA payments then. My understanding is that BMFA prefer the payment to be taken at the same as membership fees but they cannot take it if you don't have an achievement or have passed one of the idiot tests.

Cheers,

Nigel

The CAA page (link here) says "From 5 November 2019 the system will be available at Register-drones.caa.co.uk" and if you go to the Register-Drones page (link here) then that also states Registration opens 5 November 2019. So go to the Register-Drones page and bookmark it for binfire night.

Thread: Am I getting to complicated?
30/10/2019 15:52:31

I have sometimes measured rpm at full throttle with and without the Wattmeter in line to confirm that the Wattmeter is not giving a high resistance and reducing the volts at the motor below the measured input volts.

30/10/2019 14:49:00

I have had an issue the other way with a Turnigy motor, pulled 30% more current than expected and the rpm were 10% higher than expected so the motor had a higher Kv than spec. I have had another case with a cheap prop, it was relatively bendy so as the rpm increased, the pitch twisted out and the prop did not give anywhere near as much power as expected. Two lots of info you have not given is the prop rpm nor the prop type, both of which are crucial to a diagnosis.

If the motor is the correct kV of 430, then I would expect the rpm under load at 23.5V (based on your 1273 W and 52.6A to be 23.5 x 430 x 0.9 = 9,100 rpm perhaps a little lower. If you have a much lower rpm then you either have a motor that has a lower kV than advertised, or you have a high resistance somewhere in your connections or your ESC is not giving full rpm but this was discussed and cleared above.

If you are getting something like 9,000rpm then your prop is not as powerful as say an APC, you have not listed which prop you have. An APC 17x8 should be running at about 7,000rpm to draw 1237W, so again, your rpm need to be measured to help diagnose where the issue lies.

One thing that is often not understood is that the power required for a prop is dependent upon the rpm cubed. If you spin a prop twice as quickly, you need 8 times the power (2 x 2 x 2 = 8). If the rpm is down by 10% because of a slightly dodgy motor, then the power demanded will be down by 30%. For ecalc or motocalc to be within 10% accuracy on power, the motor kV has to be within 3% of its correct value.

Thread: New 78" Vulcan for twin 90mm DF
26/10/2019 17:33:37

Luckily, whilst my light ply ribs are a little warped they are not too bad so I have started the build. I will add to this thread as a sort of build log, but I am not going to make it super detailed. Tony provides a photo based instruction document which covers most of the step by step stages.

One thing I have learnt after building a kit with CNC routed parts is the router can not cut sharp internal corners there is always a small radius of 1mm or so from router bit. Therefore, I always go over all the internal corners on jigging tabs / spar slots / half joints with needle files to remove the radius, otherwise the tabs / spars / half joints do not always press home fully.

The central spine of the fuselage has gone together easily, with ribs 1 & 2. To keep them all straight and spaced during this process because of the slight warp, I have added some temporary 6mm spars from scrap along with pins, packing pieces under W2 because that sits above the building board level and set squares etc. Luckily no need for heavy weights to keep everything in place.

dsc08354.jpg

dsc08358.jpg

Thread: NEW POLL - do you use a throttle kill switch?
26/10/2019 13:46:49

I use a Hitec Aurora 9 and the touch screen on it has a throttle lock function so when moving a plane with batteries connected onto or off the runway, I always activate this and it locks the throttle off. It needs a press and hold for a second or two to activate the throttle stick, so it is in my view better than a physical switch as the throttle can not readily be activated should you stumble or fall over.

Thread: New Legislation And Trainee Requirements
23/10/2019 09:32:32

The person coming for a taster session will not have to register as an operator, clearly the instructor is the operator of the model. The same strict interpretation as noted by Steve J above has also been pointed out to me by an instructor in my club, the instructor is allowing a pilot without who has not passed competence test to fly. Whoever wrote the document probably had no idea about training on buddy leads.

Thread: Clubs as Operators?
22/10/2019 17:51:34

Additionally, for a club to register it may need to be a legal entity, I.e. formed as a limited company, and most clubs are not limited companies. Those that are tend to be those who own or formally lease their land. If a club that is not limited registers then it is likely that the committee member who completes the registration is in fact the responsible party.

Thread: New 78" Vulcan for twin 90mm DF
17/10/2019 17:47:08

Craig

Thanks for the info and photo of the smaller model showing where they belong. I have found the album containing your build pics of the 78" version, they will make a handy resource, your build is coming along very nicely. I wondered why you had so many weights on the ribs when building the fuselage. Now I have released mine from the sheets of lite ply I know, they have all taken on subtle curves.

Thread: Motocalc or Ecalc?
17/10/2019 13:54:40

There is no save option to the hard disk, just saving a link / bookmark / favorite to your browser, but it contains all the input details so you can completely get back to where you were and continue with a series of calcs. I am pretty methodical about this, here is a snapshot of Chrome bookmarks and under my Mosquito I have 2 bookmarks, links / favorites saved for ecalc with different prop sizes as I was deciding on what I wanted to go for.

There is no link to shared set ups, eCalc do not save your setup if you press share. The purpose of the "Share" button is to create a web address that you can copy and then send to someone else so that they can see your setup and recreate it quickly via email, or as I did in my post above, by putting the link on a forum. However, to save it for yourself, you need to bookmark it, or perhaps even keep a document where you paste the links in.

If you are not familiar with bookmarks / saved links / favorites then there should be general help online for your particular browser.

bookmarks.jpg

Thread: Latest CAA Update
17/10/2019 13:36:25

But aren't all clubs data controllers now anyway, BMFA went through a big thing when GPDR came in and produced example privacy policy documents for clubs. If you have members and you keep their names, addresses, phone numbers, email addresses and possibly dates of birth as well, then GPDR already applies to you so collecting the DRES registration number would just be another item of personal information. This was why BMFA went through the whole thing of the new registration system to get a system that was GPDR compliant. If you are worried that seeing someones DRES registration number is the only thing making the club a data controller then I believe you are behind the times.

Thread: Motocalc or Ecalc?
17/10/2019 13:17:26
Posted by Bob Cotsford on 17/10/2019 13:01:33:

The only thing I'd like added to it would be a simple way to save motor setups, you can give your configuration a name but I've yet to find out how to save it!

Bob,

When you have completed a calculation, press the "Share" button, this then puts a web address in your browser with all of the inputs in the address. You just then bookmark that page in your web browser. Then when you want to go back to a saved configuration, click on the saved bookmark and it repopulates eCalc with the saved configuration and then you press calculate to get back to the results where you left off.

Screenshot showing where the "Share" button is located.

ecalc.jpg

For example, here is a link for my 1/4 scale Tiger Moth setup, click here to show how the system works.

Edited By PeterF on 17/10/2019 13:31:55

17/10/2019 12:25:48

I have MotoCalc and eCalc and have used both for many years, MotoCalc right back to the days of brushed motors and Nimh batteries. Whilst I believe that both are pretty accurate, my view is that eCalc is the more flexible and has a better database of motors and props. To that extent, I have pretty much given up on MotoCalc. I bought a new PC in July and have not yet loaded MotoCalc onto it because I have not missed it yet. I also have a few EDF models and eCalc also covers these in their FanCalc module. The only thing with eCalc is you do not have a program and your data recorded, so if eCalc goes belly up, then you have to start anew.

I have used eCalc from 300W small hand launch models through the 1600W power system on the 1/4 scale Tiger Moth in my avatar, which was chosen using eCalc up to a 2500W 80in wingspan CAP232 aerobat and twin 90mm EDF jet running 2 x 3000W motors, all with acceptable accuracy.

Edited By PeterF on 17/10/2019 12:30:24

Thread: New 78" Vulcan for twin 90mm DF
16/10/2019 20:36:18

Now that it is building season I was looking around for this years build. I have a full set of gear (Fans, motors, ESCs, radio kit, servos, retracts) for a twin 90mm EDF from a former model and I was undecided between this and a couple of other options. Seeing the results of Greg's build has prompted me to choose the 78" Tony Njhuis Vulcan. I saw these flying from time to time as a child. My wife grew up in a small village north of Lincoln and needless to say seeing Vulcans in flight was a day to day occurrence for her. A huge box turned up today and I only ordered it over the weekend, soon had the contents spread out on my workbench.

dsc08317.jpg

As other people have commented, it is called a 78" model, but the wingspan on the plan is actually 83" (211cm) with the fuselage being about 75" (190cm) long.

I have one question for people who have built this, I can not find any use for the large vac formed part circled in red. I assume it is an optional cover for the end of the jet pipes, but the plans and photo build instructions make no mention of this.

dsc08319.jpg

Not sure if I will keep adding to this thread or create my own build log for this.

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