So my Turbulent is shortly to be airworthy and it’s time to think about radios. It has two magnetos but no other electrical system. The previous owner used a handheld radio connected to a homebrew antenna. It’s a homebuilt. Very much non-EASA*. Weight is an issue. And I’d like to take it to the continent at some point.
As far as I can determine, the only 8.33 capable radios approved by the CAA are the Icom A6/A24, but this approval is limited to use within the UK and possibly does not allow for use in conjunction with any external antenna.
For a mere £800 more I could fit a panel-mounted radio such as a Trig unit but would need to power it. I could do this with batteries, but would prefer to have some form of in-flight charging capability. The only electrical systems I can see for VW engines are big and heavy and designed for starter motors, landing lights and the like. It seems to me that it should be simple in principle at least to connect a brushless motor to the engine somehow to provide the 12v 3A that should be ample for both a radio and transponder.
Something like this might be ideal, though I would prefer something that wouldn’t need to be externally mounted as I feel that it would spoil the vintage character of the aircraft: http://www.ntin.net/jhardy/GenniPod.html
The aircraft is currently hand-started, and I’m fine keeping it like this.
Does anybody have any suggestions as to whether there are any minimalist alternators available that might suit? Or any handheld options that are legal on the continent? Presumably microlighters have some sort of solution (possibly to ignore the legalities?!)
*though having been built by an Englishman to a French design using a German engine it seems as European as you can reasonably get. And as an European this pleases me.
Firstly: Congratulations for your almost finished aircraft! This comes very close to what I would chose for myself if ever I would buy an aeroplane again.
Does anybody have any suggestions …
Well, the Turbulent dates back to 1951, wind driven dynamos are a lot older than that, so certainly would not spoil your vintage look. They are probably the easiest solution, simple and reliable. Another thing that comes to mind are solar cells mounted on top of the fuselage behind the pilot’s seat or on the glareshield (if your aircraft has one), which are very common with gliders. Solar cells have been around since the mid/late 1950ies together with the first spacecraft, so again won’t be a contradiction for a 50ies aeroplane. The disadvantage is that they need a larger battery and some charging electronics, but other than the dynamo they won’t increase the drag.
Do as gliders do – a large battery 
Our Cub from 1948 has a “propeller” like that – originally. Definitely “vintage”
Today, with much improved battery technology, I would think looking closer at that is well worth the effort. A modern radio like this don’t consume much, and a battery weighing 3-400 grams will last for days if you don’t continuously transmit.
However, with no other electricity concerns, no lights, no instruments etc I would think a handheld is a much simpler and practical solution.
Congrats on your progress!
Flying a Hungarian-built microlight in Belgium, with an Austrian engine, I think I may have my say
I am unsure about the power requirements for a transponder but for a handheld radio only a permanent capacity of 0,5 amp should be ample; I think 3 amps is overkill. Jesse here is of course very much welcome to correct me! But one nice point about handhelds, at least the A6, is that they have their own local batteries. These absorb the bursts of power demanded by transmitting and have plenty of time to recharge even from a modest source.
If you can accept real current technology, why not stick a couple of solar panels to your wings, or turtledeck? 12W does not require a gigantic silicon carpet. But the aesthetics would not please everybody, admittedly.
A6’s are sold in two packages, one of these includes a (switching mode) regulator to produce the required exotic 11V= supply from a car-style lighter plug. Having blown mine by foolishly inverting its power input, I have slightly tweaked an 7809 regulator (lifting its ground pin for 2,0 volts with a green LED) and it works to full satisfaction. ( Yet I am disgruntled with Icom for forcing this 11V= requirement, it sounds too much like protecting their own business and/or limiting their warranty obligations. I will not be buying from them as long as that “feature” goes.)
Because yes, my Apollo Fox came with an A6, with a neat arrangement replacing the belt clip to easily attach/detach it to/from the dashboard. It works well for me, and the A6 seems indeed to be on the list of approved radios here. BTW it is not the aviation authority that approves radios but rather the telecoms agency, www.bipt.be here They are in a building where I often go for work, I’ll go there one of these days for a bit of chat I think.
Also: I think you shouldn’t worry about 8,33 ability, your craft being – just like mine – neither of flying very high or going IFR. For a couple of years, at least, 25 KHz should do.
One issue would be that there are – to my knowledge – no handheld transponders. Here in Belgium there is no real need for one, neither in France. In Germany otoh you really want one, even if only mode C.
Lastly: that wind-driven alternator looks quite good, weren’t such things common in the 1930’s? I certainly saw one on a DH twin biplane (DH 89?) and seem to remember more. Only the spinner in your picture looks much too new-fangled.
[[later addition:]] Reading the other replies I am glad to see there is much agreement. Only, a big battery could never be suggested by anybody who has actually seen (or flown, or worked on) a Turbulent… Taking a look at gliders and their pilots is one point I meant to include but forgot.
[[more later:]] I saw your post at the other place and was about to answer there – for this kind of question it is perhaps the better place, being less focused on high end private flying – but I quite prefer to answer here, for the same reason.
Thanks for the link – even the smallest 40A alternator is 6lb though, which for me would be overkill. My little model helicopter has a 50g motor that puts out about 250 watts when driven at 12V, so it should be possible to do it lighter and cheaper.
I’m considering using 4 x A123 cells as these have served me well in aeromodelling and are, as far as I’m aware, the safest Lithium-Ion cells available.
From the Trig literature the transmitter draws 200mA in receive mode and 2A whilst transmitting. The transponder draws 300mA whilst active. I also have an Airspace Aware GPS (“<10W”). So I figured 2A at 12V was a reasonable figure to aim for.
~~~~~~
Thinking about it, I’m sure I’ve seen a little ram-air propeller coming off of an Auster wing but can’t find any links at present. I’d be really interested if anyone could provide me with any guide as to where such a turbine might historically have been sited on a vintage low wing aircraft. Presumably keeping it free from the wing or undercarriage would be best, so perhaps on the other side of the fuselage, mounted at an equivalent point to the venturi? I suspect a surprisingly small propeller would do the job. I suppose ‘approval’ would be another hurdle to consider.
Not my aircraft:
http://www.aviastar.org/pictures/france/druine_d-31.jpg
Alas, it seems this is already taken (I suspect it may have fetched as much as my aircraft).
https://s3.amazonaws.com/picollecta-pics-large/M1/PIC1000115439/KDSJJLOMNM.JPG
~~~~~~
A 20W flexible solar cell panel comes in at £90 and is 60×30cm. I had wondered about this sort of solution but as my aircraft isn’t the sort to stay outside very long I think you’d need a reasonably large cell to power the radio in all conditions.
Basically what I’m trying to avoid is the hassle of dealing with batteries and chargers – particularly for any weekend trips. It’s just another thing to have to think about or that can go wrong – radio or GPS failures can cause a lot of anxiety around London airspace, as I’ve found to my cost.
I saw your post at the other place and was about to answer there – for this kind of question it is perhaps the better place, being less focused on high end private flying – but I quite prefer to answer here, for the same reason.
I confess I asked a similar (albeit not identical) question on the other place. Not sure why. Perhaps only to confirm my suspicion that I’m likely to get more, and more useful responses here. On the other hand, one thing I definitely want to do with the aircraft is to go ‘touring’. Perhaps not ‘high end’ touring, but at least the marginal cost of flying an extra hour won’t be prohibitive and there’s just room for my bivouac tent in the back.
On the cub, we have this one today. The old one broke. This new one works just fine, and has done so for 4-5 years now on the Cub.
http://www.aircraftspruce.com/catalog/eppages/turboalt.php
A similar thing using RC parts would weigh a fraction, but you would also need some kind of “reverse speed controller” to get 13-14 V DC? or maybe you can use an off the shelf voltage regulator?
@KWLF You might want to have a look at these.
BPE-14 14 Volt / 6 Amp wind driven alternator
These are wind driven alternator, which is quite commonly used on “non electrical” Tiger Moth’s, Piper Cub’s, Austers etc. The work quite well combined with a small sealed battery, and also make it upto their rated capacity instead of the small B&C generators which Peter suggested. Tested a few of those after complaints, non of them did give anywhere near the suggested output.
I have seen wind driven generators like the one LeSving linked to installed on the belly of the aircraft between the main gear legs. I have seen one or two Austers with a different sort built into the leading edge
