Turbine or EDF
 

There are two jets I'm interested in, the BVM F-86 and the BVM F-80. Both can be turbine or EDF powered. I'm interested in those who have flown both types and which is the best choice (if there is such a thing?). I know the costs are similar etc.. Just looking for some well founded opinions.

Thank you,
BobH.

RE: Turbine or EDF
 

My opinion isn't so well founded, but...here goes anyway.

I'm slowly converting to elec on my proppies cus it's just SOOOO low-hassle and low maintenance. When you find the right batt source, it's pretty competetive price-wise too. The reduction in hassle and "stuff" carried to the field is worth the lost recip sound.

But IMO, the EDF's just sound like nails on a frigging chalkboard. Even the larger ones. Can't stand em.

My unfounded 2c.

RE: Turbine or EDF
 

I don't think large EDFs cost justify themselves as yet - not when you factor in a new set of $1000-1500 batteries every season or every other season. Flight times tend to be short too.

. . . and as mentioned, turbines sound and smell cooler. :)

RE: Turbine or EDF
 

I have built and flown all of the BVM F-86 models From the old foam wing version thru the afs to the new arf model. Recip ducted fan Turbine and now with the 5612 powered electric. The original was with a BVM .91 and Viojet and was a blast to fly. Playing with the inflight mixture control was fun and an added source of entertainment during the flight for me personally but some would say they probably hated it. The afs version I had an Jetcat P-160 turned down to what I remember was about 105,000 or so rpm but was heavy on landing and approach speeds were high. I also flew one numerous times with a P-80 and the same could be said about the landing speeds. Another that I flew had a P-60 in it and would be my choice of the ultimate turbine engine powerplant for this airplane. Turbine sounds, smells and all that. Nice landing speeds and the like. The last is the one I have now which is a BVM ARF version and is totally awsome and is powered with the new BVM EVF 5612! Flight time is about 5 minutes and performance is quite good. Better than the Recip version with the all out speed going to the P-60 turbine powered version. The sound on the other hand is whisper quiet. Not trying to be funny but it is as quiet as a black and decker dust buster. Probably quieter. If there is anything else flying you probably won't be able to here it. The last thing I would say is that it is SOOOOO! relaxing to fly. I'm not caught up in the cost of things per say but the feeling is so relaxed and others have said the same thing to me. I can't explain it but its quite relaxing compaired to my other turbine powered planes. Robbie Lynch to me the same thing. So there are my two cents. The turbine version of the ARF would be quite awsome also and the P-60 would be an awesome choice of power as well.

Tim

RE: Turbine or EDF
 

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RE: Turbine or EDF
 

Thank you for that reply. I'll be at Hamburg this weekend and I'm going to solicit opinions while I'm there. I love the sound and smell of a turbine, make no mistake about that. I was thinking of the Jet Cat P60 for power were I to go turbine. I'll talk to Bob V. at length about batter life etc. while I'm there.

Any other opinions are appreciated :)

RE: Turbine or EDF
 

I have flown the F 86 in about as many configurations as Tim, great flying airplane. I will be doing an EDF version after I finish my current project. I ilke the simplicity of the EDF setup, the instant throttle response is also a big plus. You can't go wrong with either airframe or power system.

DR

RE: Turbine or EDF
 

David thanks.

I'm looking for a source of cheaper batteries .. not sure one exists..

RE: Turbine or EDF
 

Consider other engines. Several offer more power for the same fuel or less fuel for the same power. The Wren 54 III, Wren SS, Rabbit, Merlin 90...all offer longer flight times for the fuel weight and more power to boot (from 1 to 8.5 lbs more!) for the same weight. Spend some time crunching the numbers in RCJI's comparison tables. The Merlin is the extreme example, offering approx 25% less fuel burn at P60 thrust levels, 4 lbs more thrust at P60 fuel flows, and a whopping 21.5 lbs of max thrust to grow into a later airframe with.

I love my P-60...but it's a fuel hog and more fuel = more weight.

RE: Turbine or EDF
 

Thank you. I'm also looking at the Jet Central and the New Wren 70.

RE: Turbine or EDF
 

Hi Bob,

I fly both power plants but I tend to fly my EDFs more due to their simplicity and having to carry much less support equipment.

As far as less expensive batteries go, here's the scoop. There are 3 battery manufactures in the world that make the LiPo cells we use in the hobby. Battery companines that produce packs buy cells from one of these manufactures and the companies that are willing to pay for the premium cells (cells that are evenly matched in voltage and have low internal resistance) pay more for those cells. Thunder Power is one of these companies. The lower priced battery packs are from companies that buy the left over cells and their packs may not be made up of matched cells. When TP builds their packs, they match the cells to insure longevity of the packs. Heat is a killer for LiPo packs. The internal resistance of the TP packs are so low that they don't get much above ambient temperture after a 5 minute flight. A couple of months ago two buddies flew their EDFs back to back. The ambient temp was 92 degrees. One guy was using the TP packs BMV sells and the other guy was using some less expensive packs. The plane using the TP packs had a higher amp draw than the one using the other packs. After the flights the temp of the packs were measured. The TP packs were 105 degrees and the other packs were 130 degrees. Because of the lower temp of the TP packs, they will last much longer than the other packs and the lower temp is also an indicator of lower internal resistance. As witnessed at EJets last month, an airplane participating in the speed run qualifiers was lost due to a cell in the one of the packs going bad. Guess what, they were using "cheap" packs that couldn't keep up with the 150A draw of the setup they were using. Personally, due to safety reasons and the cost of a high-powered EDF, I would never trust cheap batteries.

Kirk

RE: Turbine or EDF
 

I was under the impression that Bob V. was paying extra (and charging extra) for cell matching above and beyond TP's normal process.

As far as TP's cell holding up better than all the rest, I can tell you the first generation TP Extremes sure did not hold up worth a poop. The chinese had leap-frogged the koreans in lower IR for a while there. I hear TP's new 40C cells are pretty good though.

RE: Turbine or EDF
 

Yo Bob...

There is a line somewhere, which after crossing I will have passed from helpful to PITA. I may cross that line here, but I mean well. Bear with me please.

Why in the world would you deliberately limit yourself to the 70? There are no advantages that I can see to owning a 70 vs an SS. Maybe it's quieter or something?

My vote (not that u offered me one) is that if u are leaning toward the Wren brand, get the SS. More thrust = more options later. Virtually same $$.

If u don't require a Wren brand motor, the the Rabbit and Merlin offer more options still. I'd hate to see u covet an airframe later that u have to pass on due to a lack of ponies under the hood, my jet brother !

(Then again, perhaps I've missed something obvious in the 70's favor ?)

Sorry, I know it's none of my business and I don't mean to nag...again, I mean well !

RE: Turbine or EDF
 

Kirk, thank you. So essentially you are saying.. avoid batteries from Hyperion etc.. Go for the higher priced ones to ensure two things, longevity and safety. I guess that sums it up huh?

RE: Turbine or EDF
 

Bob

Both aircraft are very good flyers and you can't go wrong either way, they both can be flown in a sport configuration are for scale depending on what you like to do. As far as batteries are concerned the TP cells are very good and reliable, I have a set of packs with over 200+ cycles so that are still going strong and still yielding the same 6 1/2 minute flight times since day one. I still fly both turbine and edf and enjoy them both.

RE: Turbine or EDF
 

Highhorse, you do have a vote lol.. I'm always open for well reasoned discussions and yours was well reasoned :) I'll get more advice and opinions starting tomorrow at Hamburg. I'm sure I'll come home with my head spinning!.. but it'll be worth it!

RE: Turbine or EDF
 

One thing no one has mentioned so far is what is required to charge in between flights. I've seen guys lug around two car batteries just so they can do that. If you're lucky enough to have AC service at your field then I guess it doesn't matter. Also you'll probably want at least two sets of batteries if you wish to fly very often.

RE: Turbine or EDF
 

Yep, that about sums it up. Here's another thing to consider when reviewing information about batteries that you are receiving here and on the other site. The 5612 EVF (12 cell setup) draws 120A. To my knowledge, no one has successfully flown a high-powered setup with this kind of current draw over a period of time using the less expensive batteries. As mentioned above, a plane using less expensive batteries (with a 150A draw) was lost at EJets due to a cell going bad in one of the packs. They were several planes using the 5612 EVF and Thunder Power 40C batteries with no issues or failures. The guys using the Zippy, Rhino, Hyperion, XPS, etc batteries are flying lower powered setups with less current draw. The key here is the Thunder Power 40C batteries can handle up to 256 amp current draw without breaking a sweat.

Kirk

RE: Turbine or EDF
 

Whether I'm flying an EDF or turbine, I always bring a small Honda 1000 generator to power the charger. The generator and the charger is all the support equipment I bring for the EDFs.

Kirk

RE: Turbine or EDF
 

Bob I wouldn't call the hyperion packs low cost. They are not much less than the TP packs. The jet that was lost at the Ejets I believe was using A123 cells and one of the cells went dead open. I don't have anything pulling as many amps as the BVM set ups but my Zippy 25C 2200 packs work every bit as well as my 2250 30C TP Pro powers in my heli, but the Pro Powers come down at ambient and the zippy packs are rather warm. Most likely they won't have a very long life. The main problem with any of the cheaper cells or any other mfg IMO is that you will have to custom wire the packs in the proper configuration to get them to fit. Even the cheap hobby city packs should hold up ok to 150 amps if you parallel 3000mah 30C cells. Remember the BVM packs are 12S2P made of 3250mah cells. They should get you to 180 amps easy. 24 Turnigy 3000mah 30C cells at ~$10 a cell and 86 grams per gets you a pack for $240 and weighs ~4.5 lbs. Will they work, of course. Are they going to give you all the performance of the TP cells, maybe close. Last as long, maybe not. Drop in ready, NO. Get you 4 flights with out recharging for the price of one, YES. Of course if you can solder the packs right............... By the way when did the F-86 come back into play. Stop coveting my NIB F-86 and just get the F-80 [:P]

RE: Turbine or EDF
 

It was using XPS LiPo packs.

Kirk

RE: Turbine or EDF
 

Yep XPS cells. Sorry.

RE: Turbine or EDF
 

There are2 airframes that Ithink would fly really well with a Rabbit but don't really know of anyone who has done it yet:

BVMF86 w/Rabbit/Merlin90/Evo90
Tam A4 ""

RE: Turbine or EDF
 

Kirk thank you for the extra information.

Ross, the F-86 is just a consideration. The top of the heap is the F-80 :)

Here's a picture of the F-80 nose art that I intend to use.. took the pictures myself a week ago.. Extra cool!!

RE: Turbine or EDF
 

Let's say EDF is the choice for either aircraft. Which BVM system, 4010 or 5212?