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Old Nov 29, 2012, 11:09 PM
bryansifsof44's Avatar
United States, AK, Anchorage
Joined Oct 2011
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I was looking at those 1267sg servos when I was deciding which way to go for my 70". Let me know what you think... I know Tom is affiliated but would like to see them in action anyway. I decided on the hs-9754sh and love them... got them for $75 each. Also, you could get those 1267s for $95 a piece. Specs look sweet.
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Old Nov 29, 2012, 11:20 PM
Shut up and Fly!!!
jw357_23043's Avatar
United States, VA, Hartfield
Joined Aug 2011
1,004 Posts
Quote:
Originally Posted by LoneWolfRC View Post
Good points. If I get a trailer, I'd put it in the garage, maybe vent it too. Otherwise, I'd keep the plane in the garage..wife probably wouldn't like the thing come ing.

I have to do some thinking on this one...all those extras add up quick. Somebody had mentioned the airframe usually costs 1/3 of the total price, so I was hoping more along the lines of $1800...looks like I was naive.
You could always go with the 70" Extra. It flies awesome and can be set up for far less than $1800!
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Old Nov 29, 2012, 11:36 PM
Yin & Yang
Liberty10's Avatar
United States, VA, Sterling
Joined Jul 2011
4,121 Posts
Quote:
Originally Posted by Aeroplayin View Post
We had a lockout cause a brand new plane to go in after about a 50 second flight. It virtually spun into the ground. It was a while ago, but Iím pretty sure that all items went in the next airframe except the spinner and the prop. The low speed needle was bent a little. There was one other ARF gasser incident with a Pilot Extra 260 and the outcome was pretty much the same, but we did replace the two Rx and one Ignition battery in the next plane.

We also had a 27% go in after the fuel line came off the clunk while the plane was still ascending off the runway. Not much room, altitude, or speed, to do much, but it was a Godfrey kit, and the landing gear mount was built to break away so that the fuselage was not destroyed. It all worked as planned, and the motor beams and LG assembly were replaced, and itís flying again now. The prop broke that time too. Thatís the one that Tom is flying in his recent Blog videos.



The 78 Extra I just finished fits in my SUV with some thought, along with the 60 Edge, Rx case, tool case, charger case, battery box, and two passengers. The 78 flies like a big plane and presents like a 27%. The fuse is actually the same length as the 27% Godfrey, which has an 85 inch wingspan. The cost to build that plane from the ground up is about $2152 and change with top-shelf items, including:

$449.49 EF 78" Extra 300
$126.99 Shipping
$479.95 Savox SC-1267SG
$239.99 Hacker A60-16M 215Kv
$269.95 CC Ice2 HV120
$139.95 Spectrum 9 Channel Rx
$122.78 2x Gens 5300 5S 30C
$63.95 4x 5C 2100mAh 2S
$49.95 EF CF Landing Gear
$50.24 Aluminum SWG Arms
$23.48 JR Heavy Duty Extensions
$29.99 Hacker A60-Mount
$64.35 Mejzlik 22x10e
$26.99 Carbon Lite Spinner
$10.68 2 packs 6.5mm Bullets
$3.49 Retainer Clips

I was only able to save about $360 from those prices through discounts and coupons, because virtually everything that went into the plane is new. I can see an easy way to shave another $450 from this setup just by going with a DLE 35-RA gas engine.

The price list I have in mind for the 91 accessories will be next.
This is awesome Dude. The 78" MXS Airframe should come in at the same price point. If you shipped to home I can shave a few bucks there shipping it to the university. I already figured on the DLE 35RA. The rest of your setup looks pretty cool too. Thank for putting together that shopping list for me. I like to drive the 4runner if I can but I have a E250 that gets very little use sitting in the driveway that I have kept intending to use as a transport hanger.
I had a rough guess of about $1500.00. I told my wife 2K so I had some headroom just i case.

Let me ask you 2 more questions. for now that is. With the DLE-35RA what exhaust would be best and do you know if I would be able to get the sound 94 db max? My clubs 2-stroke noise limit. Hope so 1-1/2 hr drive to fly if not.. That would suck but it's def. NOT a deal breaker for me.

Aeroplayin. Thanks for sharing man. totally appreciated for sure.

Oh and cool add to the prop calc.
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Old Nov 29, 2012, 11:38 PM
Wherever you go there you are
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United States, MN, Minneapolis
Joined Nov 2011
8,455 Posts
Yeah, I'll have to debate it. I have some FPV equipment/plane that I was thinking about setting up with my son this winter...I could sell it But I think he's interested in setting it up and programming it. That, or he wants a lego mindstorm, which I think he'll get bored with (his friend has one, and hasn't touched it in months).

I think I'm going with the 91", but I'll not buy everything all at once...first the motor, airframe, pipes and mount. Then the other stuff over the rest of the winter.
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Old Nov 30, 2012, 09:49 AM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
Joined Sep 2009
6,885 Posts
Quote:
Originally Posted by propchief View Post
Aeroplayin -
I was only offering some additional data points (75-100 crashes) I've experienced or witnessed.

BTW, don't forget the header with the pipe. And check out the blazing star mount for the DA 60. I like it much better than the plywood stack.

John
Right, the header is missing too, so another $80. And, yes, there are many things that get trashed when a plane gets flattened. I saw a young gun we see fly in Deland smear his 105 inch Edge with a DLE-111 onto the asphalt runway and it looked to me to be totaled. The engine, servos, Rx, extensions, etc, all survived and even sending the engine back to Chief for repair is still much, much cheaper than a replacement. But it’s still a $1000 mistake, so you are right when you say it’s not the same as a 48 going in.


Quote:
Originally Posted by LoneWolfRC View Post
What's a more expensive engine than the DA-60? Electric? (I wouldn't do electric in this size, for the reasons I mentioned before...hard to compete with a gas motor at this size).
I was thinking along the lines of the DA-70 twin, which will probably be about $795 for the engine if DA prices it the way they typically price engines, then about another $300 for the second header and pipe.

Quote:
Originally Posted by LoneWolfRC View Post
Also, the 91" Extra comes with a pilot. Not sure about the spinner.
EF has historically sold spinners separately, and it makes sense since there are many options. I’m guessing the spinner will be an added cost.

Quote:
Originally Posted by LoneWolfRC View Post
What are the obvious downgrades?
Saving on the big stuff is the way to do it if you are so inclined. You can save about $255 on servos by going with five $99.99 alternatives (like the HS-7954H), plus a $30 throttle servo. You can go with a DLE 55 or 60 twin with the stock muffler and save a ton right there. The DA-60 setup is about $900 if you buy the motor from EF, and the stock DLE 55 setup is $370. So that’s $780 so far. Using a 7 channel Rx instead of the 9 channel will save another $50, and another $42 with a wood prop…. So we’re saving close to $880 with these four items.

DLE makes a tuned exhaust package for $150 if you wanted to go with the DLE but keep the tuned exhaust, which brings the savings back down to $730. You can probably make up another $60 by going cheap on switches, going with H9 arms, dropping the Fiji tank setup since I’m sure it comes with a tank, going with one Rx battery, and maybe you have some Velco and connectors laying around from another project.

So potentially, there’s a $900+ savings depending on what sacrifices you want to make, and if you are like me, you probably have another $200 in available items in your parts box. Personally, I think that if getting the plane in the air is important to you, then you can do it for $2200 without putting the investment at risk. For the guys up north that have some time before decent flying weather returns, this project becomes a lot of fun and you can space out the spending over the next few months too, while you look for good alternative items at decent prices.

Liberty10... About the DLE-35R on the 78, I'm sure the ES30G CF tuned pipe should keep the engine noise down, but there are muffler silencers around too. I have no experience with then and use electric motors to keep things quiet.

But a lot of noise comes from the ripping prop, which is when tips break the sound barrier. They make a ripping noise that some guys mistake for engine noise, but 's clearly not. If you get the RPM reading, you can calculate the tip speed using Pi times Diameter to confirm this.
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Old Nov 30, 2012, 11:21 AM
Yin & Yang
Liberty10's Avatar
United States, VA, Sterling
Joined Jul 2011
4,121 Posts
Aeroplayin,
Couldn't quite grasp that formula but doing simpler math (if I did it correctly that is)
Ok put together a quick calc in excel to figure this out. I think I got it right.

22" @ 8400rpm is 549.7625mph

Ok I did a quick search and there was a note that stated prop efficiency should be crap lost the link. I think it said .87 - .9??? mach 550mph @ 80F = .706 Mach. That can't be right.
Can you tell me where I got it wrong?

Edit: Ok found that link again and got it wrong. above It read .88 to .92 mach is red line. No actual best was given it was a calc as well based on the area of the prop disc. Dag nabbit work keeps interfering with my thought process here. I'll get back to this in a few...
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Last edited by Liberty10; Nov 30, 2012 at 11:53 AM.
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Old Nov 30, 2012, 11:41 AM
daedalusrobert's Avatar
United States, GA, Valdosta
Joined Jan 2009
609 Posts
Anyone else ever feel like Penny?
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Old Nov 30, 2012, 12:05 PM
JKasprak
propchief's Avatar
Fayetteville, NC 28304
Joined Jan 2010
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Quote:
Originally Posted by daedalusrobert View Post
Anyone else ever feel like Penny?
Many times - you're not alone there.
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Old Nov 30, 2012, 12:25 PM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
Joined Sep 2009
6,885 Posts
I love Penny, and my wife and I have a similar relationship... she actually went blonde this week and had her first blonde moment last night at dinner. well, maybe not her first.

Correct... Tip speed is calculated this way...

Tip Speed in ft/sec = ((((Prop Diameter in inches) x 3.1416) x RPMs) / 12 inches) / 60 minutes)

So your 22 inch prop rotating 8400 RPMs means the tips are moving at 806 ft/sec, which is about 550 mph.

The speed of sound at sea level is about 1,116 ft/sec or 761 mph so no problem there.

22 inches x 3.1416 = 69.12
69.12 = one rotation in inches
8400 = rotations per minute
580568 = inches per minute
9676 = inches per second
806 = feet per second
48381 = feet per minute
2902838 = feet per hour
550 = miles per hour
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Old Nov 30, 2012, 12:27 PM
Yin & Yang
Liberty10's Avatar
United States, VA, Sterling
Joined Jul 2011
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Quote:
Originally Posted by daedalusrobert View Post
Anyone else ever feel like Penny?
I was so wrapped around the numbers I scratched my head the first time I read it.

LMFAO.
Thanks I needed the laugh.
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Old Nov 30, 2012, 12:48 PM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
Joined Sep 2009
6,885 Posts
Quote:
Originally Posted by jw357_23043 View Post
You could always go with the 70" Extra. It flies awesome and can be set up for far less than $1800!
Yeah, I've been thinking about the 70 EXP for a long time now because, just like the 60, I can fit it in the SUV with the 78 EF Extra or the 85 Godfrey Extra.

$389.95 EF 70" Extra 300
$349.95 Mini Servos
$182.75 A60-7S V2 215Kv
$189.95 CC Ice2 HV80
$64.83 EF Shipping
$89.99 Rx
$50.24 Arms
$23.48 Extensions
$21.59 Xoar 20x10 PJN
$8.99 Spinner
$3.49 Retainer Clips

Total $1,372.41 plus shipping for other components
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Old Nov 30, 2012, 01:01 PM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
Joined Sep 2009
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You can get that down to $1,234 by going with a ZTW 85A ESC, but I'd add another twelve bucks for a separate 3S Rx battery.
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Old Nov 30, 2012, 01:26 PM
Shut up and Fly!!!
jw357_23043's Avatar
United States, VA, Hartfield
Joined Aug 2011
1,004 Posts
Quote:
Originally Posted by Aeroplayin View Post
Yeah, I've been thinking about the 70 EXP for a long time now because, just like the 60, I can fit it in the SUV with the 78 EF Extra or the 85 Godfrey Extra.

$389.95 EF 70" Extra 300
$349.95 Mini Servos
$182.75 A60-7S V2 215Kv
$189.95 CC Ice2 HV80
$64.83 EF Shipping
$89.99 Rx
$50.24 Arms
$23.48 Extensions
$21.59 Xoar 20x10 PJN
$8.99 Spinner
$3.49 Retainer Clips

Total $1,372.41 plus shipping for other components
You really got that servo price low! Mine was a total of $446 with 5955TG on rudder/ail and 5245 on the elevator. Maybe I went a bit overboard! Anyway, why the 215kv? I have the 310kv and it's way more than enough on 8s.
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Old Nov 30, 2012, 02:05 PM
Yin & Yang
Liberty10's Avatar
United States, VA, Sterling
Joined Jul 2011
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Quote:
Originally Posted by Aeroplayin View Post
I love Penny, and my wife and I have a similar relationship... she actually went blonde this week and had her first blonde moment last night at dinner. .
My wife went blonde not long after we met. There have been many such moments over the years. Oh and we both love Penny. wouldn't be right without her..

Quote:
Originally Posted by Aeroplayin View Post
Tip speed is calculated this way...

Tip Speed in ft/sec = ((((Prop Diameter in inches) x 3.1416) x RPMs) / 12 inches) / 60 minutes)

So your 22 inch prop rotating 8400 RPMs means the tips are moving at 806 ft/sec, which is about 550 mph.

The speed of sound at sea level is about 1,116 ft/sec or 761 mph so no problem there.

22 inches x 3.1416 = 69.12
69.12 = one rotation in inches
8400 = rotations per minute
580568 = inches per minute
9676 = inches per second
806 = feet per second
48381 = feet per minute
2902838 = feet per hour
550 = miles per hour

My formula arrange a little dif. than yours but gets to the same place.

(((( Prop Diameter x 3.1415) / 12) x 8400) x 60) / 5280 = 549.76
I did not compensate for elevation but did for temp.
((ambient temp. x 460) Squared) x 33.4

@ 80F + 460 = 540 sqrt of 540 is 23.238 x 33.4 yields 776MPH at 80 deg. F

550/776=.71% of Mach @ 80F

Found that AMA recommends getting below .75 Mach to keep noise down. I also found that full size props are most efficient between 70-75% of Mach. So that seems a good starting point for efficiency.

Not sure if the motor will actually turn 8400 with that size prop but I now I have a spreadsheet with the formulas set.

I'm no Leonard but I do really like this stuff.
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Old Nov 30, 2012, 03:43 PM
Byron C
3DeltaFly's Avatar
United States, TN, Knoxville
Joined Apr 2011
726 Posts
Quote:
Originally Posted by jw357_23043 View Post
Anyway, why the 215kv? I have the 310kv and it's way more than enough on 8s.
The A60-7S is for a 10S setup, thus the 215kv I'll be using this same setup in a 74" Edge
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