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: Latest CAA Update|
The CAA consultation site ( **LINK**) is still showing 16th September as the expected date for the response document to be published. Now overdue. Perhaps due to the recent ministerial intervention.
|Thread: Forum members' new models: Let's see them.|
Are newish or half new models allowed in the thread.
I have an 81" Brian Taylor Mosquito that flew with RCV 60SP engines for a number of years. I had an engine out incident a couple of years back and could not get back to the runway and the model landed in a hollow in the rough pasture outside our field. The fuselage did not actually hit the ground as the wings landed on the lips of the hollow. The fuselage was hardly damaged because it did not tough the ground, but the wings were badly broken. I have now built a new wing rather than trying to make major structural repairs. As I have converted entirely to electric flight in the meantime, I have rebuilt it as electric power. Interestingly, the electric version weighs 17lb 12oz ready to fly, the IC version weighed exactly the same dry (without fuel).
Hyperion ZS 4025-16 320kV motors with 16x12 APC E props driven by 6S 4000mAh batteries through HobbyWing Platinum 80A V4 ESCs. Measurements gave 6,450rpm at 22.3V with 47.5A, so about 1050W each = 2100W. The pull on the ground was tremendous and much more than the RCV 60SP engines which never reached much above 5,500rpm on 16x12 props. The RCV engines flew the model sedately, the motors will give a potential 20% boost to top speed, but more importantly 40% more thrust, which is why it felt so powerful on the ground.
|Thread: free PDF to DXF software|
I have used scan2cad previously for some large A1 or A0 drawings, had quite a few good settings to clean up drawings but took a while to get used to it. It may not be free any more, just free trial.
|Thread: Using larger lipo to charge smaller one|
I fly some larger electric models and field charge. My field pack is made up from 6 x 6S 16,000mAh packs in parallel giving 96Ah. These are the cheaper 10C Turnigy / HobbyKing Multistar packs that I believe are now discontinued. This is lighter than lugging about a lead acid leisure battery and has close to 2.5 times the usable capacity of the larger 110Ah lead acids and one lead acid battery would not be enough for a full days flying and I did not want to go the generator route. I am now well into my second full year of use and I have no problems at all with using this. It seems to be an eminently sensible option.
|Thread: Hitec Optima Aerial Mount|
Wheelspin Models have these as shadow stock, could check with them to make sure that they can source them before ordering.
|Thread: RPM Conundrum|
I had an IC twin once that ran 10x6 APC props, I tested 7 props one after the other on one engine and found something like a +/-200 rpm difference at 10,600 rpm, so even props can have a little variability.
|Thread: Electric Motor 'clunk' When Opening Throttle|
I had this on a Hyperion motor and changing ESC settings did not help and neither did it have any end float. I finally stripped the motor down and the stator coil could rotate a little on the mounting shaft. There was a small piece of about 1mm rod that fitted into a groove on the outside of the shaft and the inside of the stator to stop the stator from rotating. This rod was too small, so I removed and fitted a slightly larger bit of piano wire and the motor now starts up with much less clunking or hesitation.
|Thread: CAA registration consulation|
This is what I have replied about these numbers in consultation and letters. As has been stated elsewhere, in terms of what we spend as modellers it is a small number, so I will pay, I have made my displeasure known but I will not be taking an enforced break, flying without registering etc.
I have a serious concern of the method used to arrive at the 170,000 registrations over the initial period. This was calculated as a per capita average of registration take up in the USA and Ireland, two countries that are culturally different to each other. Ireland being closer to the UK should have been used as the basis giving 128,000 registrations. This would increase the £16.50 charge closer to £22.00. The charge ($5 for 3 years) on an annual basis in the USA is just over £1/annum and in Ireland (€5 for2 years) it is just over £2/annum. The fact that the CAA is proposing a charge 10 to 20 times higher than the countries that Tthey based your statistics on means that the charge will actually be a disincentive to registering and will act to reduce the per capita registration in the UK. This means that the purpose of the scheme to ensure education of drone users is not met.
The CAA could tell many months ago before the recent updates on that page when they gave model aeroplanes and helicopters below 7kg the >400ft exemption but not "drones".
The 170,000 figure, right or wrong is their estimate for the number of registrations in the first 18 months stated clearly in the consultation document, not the initial sign up, so a Winter break may be pointless in trying to show them that the number is wrong.
Edited By PeterF on 17/05/2019 09:12:02
The operator registration and pilot testing are going to happen regardless of the cost and the vast majority of us are both operator and pilot. I am the secretary of my club and the thought has just struck me, what tack should a club take vis a vis the registration and test status of its members. Do we need to take the active role of ensuring that our members have current registration and test passes to their names, I do not know that answer at the moment, I have just started sound checking, I really do not want to be policing more stuff. What is BMFA's stance going to be on this and will their insurance cover you if you are operating illegally by not being registered and having passed the test.
|Thread: LiPo Internal Resistance|
That is the same calculation method as the one I referenced above on RCGroups and gave the equation for, just coded up by someone else, although they have extended it to calculate the voltage drop that occurs at maximum current.
I knew it was somehow related to heat generation, taking the equation apart explains it well. The constant 6 will effectively be the combination of battery mass per mAh, specific heat capacity and an allowable temperature rise. There are a range of battery weights for a given mAh rating, so a better equation would be based on that, but the one shown seems to be sufficient.
I believe that your arbitary 30% increase in IR is very conservative and will result in you dumping batteries prematurely. Use the calcualtor or the equation and see how things pan out for a 30% increase in IR. Because the formula is square rooted, this make a 30% increase in IR about a 15% reduction in C rating. I believe that you can normally absorb a much larger reduction in C rating before seeing issues.
The equation was published at some point if you want to make up your own spreadsheet to calculate things backwards rather than working the on line calculator iteratively.
Max current = square root(6 * Capacity / IR )
Effective C rating = 1000 * Max current / Capacity
Max current is in Amps
Capacity is in mAh
IR is in mOhms and is the IR of the cell with the highest IR in the pack.
The milli in the battery capacity and the IR cancel each other out.
I believe that if you have good batteries that over time you could let the IR double if they are still working. I have some 2200mAh batteries, new 7mOhm, aged 12mOhm, the calcs above suggest that the C rating has fallen from 20 to 15 and they still work OK in planes that draw 25Amps, although they are warmer at the end of the flight and flight duration is down compared to the new ones. However, my 3700mAh batteries that are my mainstay now have IRs of around 14mOhm (no record of as new) giving effective C of 11 and in one plane that draws about 55 to 60A they are now very sluggish.
Edited By PeterF on 26/03/2019 13:40:38
Have a look at the following RCGroups thread on this subject and the calculator for determining max continuous current from cell capacity and IR. **LINK**
|Thread: RCV Engines|
Here are a couple of photos of the installation of an RCV60SP in my mosquito, I put scoops into the cowls from the air inlet below the spinner curved through 90degree to the the air flowing vertically over the fins. All air entering the inlet flowed into the scoop and the scoop was quite tight to the fins so all air flowed through them and not around them. The air exits were furtehr back in the crankcase area. I had no issues with engine overheating with this set up.
I have same comment as Don regarding lengthy running in, although in my case I kept a high tickover speed to avoid dead sticks as the Mossie landed quite fast this was not an issue.
|Thread: RCM&E Fly-In 2019 - general chatter|
I'll see what David says as the linked page says "the hangar which we’ll equip with a small bar and use for evening gatherings and casual indoor flying", so it may not be available for storage.
If I bring down a large biplane for the weekend will there be anywhere to leave rigged models overnight on the Saturday, or will these need to go back in the car overnight. I had also heard Barkston was installing power for charging for flight batteries, any idea if this is true.
|Thread: Flair Tiger Moth, help needed.|
You could try registering with RCScaleBuilder (www.rcscalebuilder.com) site as there have been quite a few Flair Tiger Moth threads on there and contacting the people who have built them.
The CoG should be located at the rear of the fuel tank, I have seen that mentioned in the Flair TM threads and that is where the Falcon Models 1/4 scale TM that I have balances. Can't help with Flair TM plans I am afraid.
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