Hawk owner- first lectric model( thanks to Timbo)

[Myron Beaumont]

Just received latest mag  Lots of very cheap batteries etc in it (told you all everything changes month to month) .I might make the Hawk into a high wind glider & use my 'lectrics for a home scratch build ? with bigger wing area .Who knows ? (Myron  in the home for the bewildered ! )

[Tim Mackey]

Forget the Imax5, apart from anything else, it will be useless when you come to want a 6s pack...which one day you probably will.

Yes you need a wattmeter or similar...I believe BRC may have one on offer at the moment. Without one,you will not know for sure whether you are overstressing the battery /esc /motor etc. The first time you use it, you could save the initial cost twice-over.

As for field spares, well personally I never carry any these days. I used to have the lot - cable, connectors, collet adaptors, gas soldering iron and solder, etc etc. Now, I might be able to find you a chocbloc connector and the odd blind nut if you are lucky - and I dont even know why I carry those either !. If I have the misfortune to need repairs on any of my models following any mishaps ( thankfullly very rare these days ) I prefer to get it home, and look at it properly in the workshop over a nice cup of tea and a sticky bun. I have seen too many bodged repairs done at the field for my liking...'tis just my way

Cheap batteries are everywhere, and some are better than others. The not so good ones will simply NOT hold their voltage when asked to work quite hard ( such as in EDF ) and which are good and which are bad is not something I can or will publish here. All I can say is, that top branded items such as flightpower / thunderpower /kokam etc reflect their higher cost with good performance. Personal recommendation from those who have used them is the only real way to avoid buying a lemon - and before you say it yes I know a lemon can be made to act like a battery...but trust me - it is NOT going to spin your EDF

[Myron Beaumont]

"Proper job "as we said down Cornwall.Scott has told me that a 6 s  pack is the way forward although he's offered me a smaller one and Im getting a bit more confused. Zippy lipos come in at £25  2200Mah & 168g ? Not enough volts I hear you say it is a 20 C pack& features JST-XH  balancer plug . Dont know why the writing has changed ?    'tis becoming a hot line on this thread of ours .Another message or two on the way .Maybe other ignorami can learn from my thread/ questions /stupidity etc

must get off the nitro !

[Tim Mackey]

I thought Scott said the motor with the fan you are having off him is best run on a 4s LiPo NOT a 3s and certainly not a 6s cos of the weight problem as we have already discussed.

You will probably need more than 2200 mahr too !

Are you getting confused between a 6s Lipo battery, and a 6s capable charger ( Imax 5 versus Imax 6 )

[Myron Beaumont]

I don't know    but  I'll probably end up with lots of spares I can help other poor semi-converts like me with !   Need some more Nitro

[Myron Beaumont]

PS   'er indoors has just brought back some "Just for Men " Is she trying to tell me something?

[scott cuppello]

Have sent 22c 4s 2200mAh Lipo, which is what it ran in the F-20, it's best to get a 6s charger these days because 1 - The price difference between 5 & 6s chargers is now negligable 2 - So much stuff is going 6s now...it's only a matter of time.

[Myron Beaumont]

PSS    Scott said he has a 4s I can have which I agreed to buy .Then another message came through about the 6s ! I shall have some more nitro

[Myron Beaumont]

Thanks Scott    Talk about a hot line . I m sorry if I'm taking up a lot of your time but it's Timbo's fault as you know         Do you sell fuel    Are you actually in Cumbria ?  not far away as the ic powered A/C flies?

[Myron Beaumont]

Scott & Timbo     Been thinking !   Timbo -Have printed off your Lipo charge level  document hoping it might help eventually .Now then ,do you have a  weight  /watts//power / wing area /wing shape/etc. chart handy ?(for 'lectrics )

[scott cuppello]

Fuel? No mate.....

[Myron Beaumont]

Scott    I'm getting the picture thanks .Got to think of the future eh .I m trying & cant wait to send you the fly cam of its first (last )flight  Looks like a 6s charger ! Only joking about fuel ! Got loads in 'er indoors's shed  BUT she's non too happy about Lipos 'cos she's seen all the threads .I shall not perturbed in my latest venture however. Thank you to all three of you both again !

[Tim Mackey]

Myron. The only power "chart" as such for leccy flight that I use is the "watts per pound rule"

Now some folk will doubtless take issue with it, but this is my usual guide ( I dont drill down that deep as to worry about wing area /shape/airfoil section and stuff ) - all figures are Watts Input, per pound of AUW.

1) Slowish scale type high wing model - 75Watts ..... EG 2lb model AUW ....aim for 150 Watts Input.

2) Medium speed type general aerobatic aeroplane ( think Edge, acrowot etc) ... 125 Watt

3) Fast pylon racey type thingies 150 Watts.

4) EDFs - Yippee now were cooking 200 Watts.

Good guideline, but in this game, generally speaking...more is good - we do actually have throttles you know

And remember the good 'ol modellers motto "add lightness" ? ....well never before in the history of man has so little meant so much, we call upon every man to do his .....

oops, sorry came over all Winston then

Seriously....throw out the epoxy and plywood, and get used to minimalistic, CA, liteply if you must, and foam !!

[Myron Beaumont]

Winston   Whoops sorry Timbo!  I was it seems confused about the "6" issue .Hopefully I understand what I'm talking about now ('til the next time that is?)  Have just received 14.8V 2200 mah 22C (burst40C)  48A Electrolite  Lipo /Hifie ESC 45 A G SE 4A switching BEC /AP 700  2200KV  outrunner(70 mm fan    courtesy of Scott   Flying weight will now be 860 gms (plus glue !)

Thanks Scott - cheque is in the  post as they say

Now then (here we go)what is the BEC ?please .Maybe I should be on the "Newbie" thread?

[Tim Mackey]

It supplies the low voltage required for your radio, from the higher voltage battery that is powering your motor.

Read this Myron.

http://www.modelflying.co.uk/forum/forummessages.asp?dt=&UTN=1882&last=1&V=1&SP=

Me thinks you need to spend some time reading a lot of the old threads on here, which, in your dinosaur days, you obviously chose to ignore

[Gareth Wallis]

I brought the hawk from Als last year. I had one 2 minute flight using 25c 3200 3s then the recomended 60amp esc melted. Shop replaced it with 80amp esc. Tested setup and watched in dismay as the motor slowly melted the motor fan housing! .....heard they pull 90amps on this set up.

After getting my cash back i brought a topgun parkflite hawk RTF. After a few tweeks it flew great , a nice size , fair speed , and gives 8-10 mins fly time drawing 20amps. Have now upgraded esc,1800 4s pack , spektrum radio. BLINK AND ITS GONE!  - just very fragile.

[Myron Beaumont]

Timbo     Have been ploughing through the various threads (mostly yours ) to get up to date on what exactly I've let myself in for, as you recommended,& have more questions AGAIN!than answers.

#1      Am I starting off with something maybe I should tackle later ie after some training on a normal A/C only lectric ?

#2      If so can you recommend anything knowing what gear I now possess Maybe something that is a wee bit slower (cos my eyes are getting worse through looking at this screen by the hour )

#3      Cant find an affordable I max 6  .Should I get just a charger + a balancer & if so any different connectors to suit

#4       Dont think that if I could afford a Wattmeter that it would go in the fuselage to measure current flow  so if I restricted myself to using max rpm on take off only would I get away with it?& I think I can answer that one!

#5        Not happy about inlets interior shape on the Hawk -Should I shape the ducts into some sort of aerodynamic decent shape(withfoam or balsa etc.)?

#6       Should I make it so that I can "get at the fan unit  as the way it is shown once in its in for good ie cut away a largish hatch above or below centre line of fuselage

Thereis a lot more to ask but so far havnt lost what Im writing  so will snd this off before it all disappears into the ether AGAIN      CHEERS  Myron   ( Ether----MMMMM  memories!)

#7        Best place for the ESC to keep it cool  (in the inlet ducts?)

[Myron Beaumont]

PS Gurus out there.  Just spotted Ripmax Pro peak prodigy  charger BRC special offer   £40

Wattage DCM Wattmeter                                                                                    £33

Balancer                                                                                                                 £15

I kow you cant comment on particular makes & models etc but what do you think considering alternatives corrently available?

[Tim Mackey]

Well once you add up the cost of the pro peak ( which is a good charger BUT only goes to 5 LiPo and you are advised to get one that will jhandle at least 6 cells remember ! ) and the balancer, you are 55 quid.

I dont believe you cant get an Imax6 or suitable clone for around that money. I paid well less than that for mine, and that included shipping from HK ! I have seen this very charger here on a UK site for £44

You MUST buy a watt meter. The one at 33 quid you mentioned will beTHE best 33 quid you will ever spend in electric flight. FULL STOP. If you dont get one and use it, I will not continue to help you in your electric flight ventures.... sorry to be so harsh, but I cant reinfiorce the need to use one enough!!.

you didnt read this ??

PS you dont fit it into the aeroplane my friend....you just hook it up for the bench testing.

Your other questions in the first post above.

1. Well yes you are going in slightly at the deeper end. Recommend alternatives which utilise exixting gear -thats a tough call because 70mm fans and high KV motors and 4 s lipos are not common place for beginners, however if you can stand the cost of other batteries then the "beginners" stuff from flyingwings.co.uk ( trade partner here ) are great intros into electric flight. Most of these models come with motors, and some with ESCs...but if you ask nicely you could probably get a model and motor only. That way you could use your existing ESC and just buy a small 2s or 3s cheapie Lipo battery...indeed I probably have a few here which you could use if you wanted them.
2. See above.
3. see above
4. see above
5. Yes
6. good idea if practicable
7. Not always easy. You need to be careful not to restrict the smooth airflow in the ducting either inlet or outlet. I tend to just use an ESC which is rated quite a bit higher than its likely to be drawing ( current ) and leave it inside the fus. The other problem is the length of leads from the ESC to battery and motor, so sometines ...it is a compromise. I have NEVER fried an ESC through lack of cooling.

[Myron Beaumont]

Thanks to you both   (more research done-AGAIN )    Off topic --regarding" another place  " Is he really Paul Daniels ? .If so, maybe he can help me in my month of need ? Does he want an unused Optic 6 set up I wonder--- to help pay for my transition to the black (magic) art

[Myron Beaumont]

Jetsome    Which one that I've used should I get rid of, except the one that has caused me an unfulfilled lifetime of modelling pleasure WHere's that nitro gone?

[Myron Beaumont]

Timbo

Thanks again my friend /helper/guru .I realise that the Wattmeter won't be inside the A/C  Only thought it could be used in situ BUT whats the point of using one "on the bench " when so many parameters change in situ ? Especially when it's travelling at a rate of knots? Hence the apprehension ! OR maybe there's a graph somewhere showing differences in the interaction between all the variables   Makes me remember that yonks ago I produced EPR (engine pressure ratio ) charts for various A/C with RR gas turbines eg  SPEY  -all variants civil & military .

 Now I dont know how well I might get on with 'lectrics ,maybe I'm being too ambititious (a fault of mine ) so perhaps some smaller Lipos as you said & a 5s max charger and built in balancer  is the answer for the moment 'til the latest batteries come down in price (due to demand AGAIN) .I'm right aren't I in saying that this game is never quite up to date ever (lectrically)

[Myron Beaumont]

I am trying       VERY