SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Feb 02, 2010, 11:45 PM
in way over my head
The Bambozler's Avatar
Memphis, TN
Joined Feb 2010
100 Posts
Question
EDF F/A 18 vs. F-22 advice/MFG

I will try to keep this straight to the point:

1. I really like the looks of the Tiger Meet F/A 18 70mm EDF at Bananahoby.com. I have googled like crazy to see and hear input about it. It has been about 50/50 love/hate. I need to know if their stuff is hype or if it is good. The plane is made by blitzrcworks...

2. I like the SAPAC F-22 airframe. I am not crazy about the paint. Seems like it could look more scale. I like the specs: .95ish wing loading, nearly 1:1 thrust to weight. I can paint the tiger scheme on the 22...

Anyone have direct experience with these two EDF's? I am not new to R/C, just the EDF's. I have lots of stick time, but I am thinking the F22 would be better for EDF noob... What about a gyro for ailerons? Quality of electronics included with these two?

I have a JR642 for TX so I can use the features it has to offer. I just need some advice instead of an advertisement.

Please help. Thanks.
The Bambozler is offline Find More Posts by The Bambozler
Reply With Quote
Sign up now
to remove ads between posts
Old Feb 02, 2010, 11:48 PM
Team White Llama!
gundamnitpete's Avatar
Joined Jan 2008
8,144 Posts
Get the sapac f22 and replace the stock esc's with 50 amp ones, and run it on 4S.
gundamnitpete is offline Find More Posts by gundamnitpete
Reply With Quote
Old Feb 03, 2010, 07:26 PM
Were..is..my..Super..Suit ..
j3tman's Avatar
United States, NE, Papillion
Joined Sep 2009
2,510 Posts
the sapac f22 would probably be mush better quality, and the f22 has a good glide ratio. One quick question if you do get the f22 will it be with retracts or fixed gear?

but im not saying the bh f18 is bad or anything just banana hobby, when you order a plane (even if its a good plane ) you always have the of a defective one.

so im going with the sapac f22.
hope this helps
j3tman is offline Find More Posts by j3tman
Reply With Quote
Old Feb 03, 2010, 08:57 PM
in way over my head
The Bambozler's Avatar
Memphis, TN
Joined Feb 2010
100 Posts
Seems like F22...

I agree about the glide ratio, as well as the "specs" listed for this airframe. Don't know about retracts... My radio is only 6 ch, (JR642) 72 Mhz. so I don't think the retracts would work out. This radio is a programable, mixer etc. I am used to it, etc. I know 2.4gHz is better, I just don't want to spend to $ at this point...

I am new to electric propulsion as well as EDF. It seems very complicated. The previous post said to upgrade to a 50A speed contr. I looked at the specs given at Fan Jets USA and it said only to use a 3 cell batt on the supplied SC. I am still trying to figure out the basic "global" propulsion system, and some of the specific info that I read is very confusing. I think an algebra refresher may be in order, as well as some specific EDF knowledge.

I am tired of wiping down my glow planes after flying, tired of the ground support (starter battery, ignighters etc.) and dead stick landings, esp. at low altitude and air speed, etc. Want the EDF for the new thrill, airframes are bad ass, my kids love military jets...

My plan is to try not to get a dificult airframe (hince the F22) and I really do not plan to "hot rod" it for two reasons:
1: A slow flying style for stick time with new airframe and,
2: Propulsion knowledge.

I have kicked around the idea of aileron gyro for takoff/landing stability and later high angle of attack at low speed (ALFA?) so, pointers on this would help also. Heli's use heading gyros, so why not aileron? Don't know...

I know that EDF's need a certain amount of throttle to maintain flight, I just don't need to tear the sky apart on my way to a crater. Been there, done that, got the fire wood to prove.

Thank you for your opinion. I hope readers understand that I am not just some total noob with no knowledge. I hope to hear from as many of you as possable. I really do research on these topics and am studying and working these questions on my own, so your help really saves me time.
The Bambozler is offline Find More Posts by The Bambozler
Reply With Quote
Old Feb 04, 2010, 12:13 AM
DqP
Alert5 RC International
USA, FL, Fort Lauderdale
Joined Jul 2009
170 Posts
The Sapac F-22 is one of my favorites. I agree, it's screams on 4S but draws about 60A peak. I've got a stock one with upgraded to 50A ESCs and it's a blast to fly. I've got a second one with upgraded motors, 50A Esc and screams on 3S.

I love this airframe because you can fly it fast for float it in low throttle. it also lands very stable and you can float it down if you need. you can definitely high alpha it slow flight.

I've posted a video on my youtube account with my stock F-22.
Sapac F-22 - Maiden Flight (3 min 32 sec)


I'm getting ready to post another video with my upgraded setup.
DqP is offline Find More Posts by DqP
Reply With Quote
Old Feb 04, 2010, 01:31 AM
Team White Llama!
gundamnitpete's Avatar
Joined Jan 2008
8,144 Posts
Quote:
Originally Posted by The Bambozler View Post
I am new to electric propulsion as well as EDF. It seems very complicated. The previous post said to upgrade to a 50A speed contr. I looked at the specs given at Fan Jets USA and it said only to use a 3 cell batt on the supplied SC. I am still trying to figure out the basic "global" propulsion system, and some of the specific info that I read is very confusing. I think an algebra refresher may be in order, as well as some specific EDF knowledge.
The stock speed controls cannot handle the amount of amps the motors will pull on 4S. That's why you need 50A esc's.

Here's a pretty basic understanding:

The KV of the motor times the voltage you supply (11.1 volts for a 3S lipo) eqauls the "no load" rpm. Like running a glow motor with no prop, it's gonna spin faster than if there was a prop, or load, on it.

so, if you have a 4000kv motor, and you put 10 volts into it (roughly a 3S battery), it wants to spin 40,000 rpm. Because the fan is a "load", it will most likely spin around 35,000 rpm or so.

If you put that same motor and fan on 4S (roughly 15 volts), you get 60,000 rpm. The load on a fan increases exponentionally(basically, you need 8 times the power to double the RPM), so the "load" on 4S is great than on 3S. this causes the motor to draw more amps.

So, if you draw about 25 amps on 3S, going to 4S will bring your amps up to around 35 or so.

25 amps on 3S is around 250 watts (10 volts times 25 amps). 35 amps on 4S is around 400 watts (14 volts times 35 amps). So, as you can see, increaseing the voltage by one cell can have a huge effect on the total power out.

Just remeber, if a motor says it's good for 900 watts, that means that you can load it to that much, don't expect it to pull 900 watts in every fan on any voltage.

For instance, if you buy a fan and motor that's been assembled, and it makes 1500 watts on 5S, if you drop it to 4S, it's not gonna make 1500 watts (less volts, less load). It will make more around 800 watts on 4S.


Quote:

My plan is to try not to get a dificult airframe (hince the F22) and I really do not plan to "hot rod" it for two reasons:
1: A slow flying style for stick time with new airframe and,
2: Propulsion knowledge.
good start, just remember that electric is no more complicated than glow. It's not like you were born knowing how to tune your engines right?

Quote:



I have kicked around the idea of aileron gyro for takoff/landing stability and later high angle of attack at low speed (ALFA?) so, pointers on this would help also. Heli's use heading gyros, so why not aileron? Don't know...
maybe save that one for after you get a few good edf's flying, don't want to over complicate things.
gundamnitpete is offline Find More Posts by gundamnitpete
Reply With Quote
Old Feb 04, 2010, 07:23 AM
Checking CG is for NERDS!
Smokescreen38's Avatar
Joined Jun 2005
5,347 Posts
Quote:
Originally Posted by gundamnitpete View Post
The stock speed controls cannot handle the amount of amps the motors will pull on 4S. That's why you need 50A esc's.

Here's a pretty basic understanding:

The KV of the motor times the voltage you supply (11.1 volts for a 3S lipo) eqauls the "no load" rpm. Like running a glow motor with no prop, it's gonna spin faster than if there was a prop, or load, on it.

so, if you have a 4000kv motor, and you put 10 volts into it (roughly a 3S battery), it wants to spin 40,000 rpm. Because the fan is a "load", it will most likely spin around 35,000 rpm or so.

If you put that same motor and fan on 4S (roughly 15 volts), you get 60,000 rpm. The load on a fan increases exponentionally(basically, you need 8 times the power to double the RPM), so the "load" on 4S is great than on 3S. this causes the motor to draw more amps.

So, if you draw about 25 amps on 3S, going to 4S will bring your amps up to around 35 or so.

25 amps on 3S is around 250 watts (10 volts times 25 amps). 35 amps on 4S is around 400 watts (14 volts times 35 amps). So, as you can see, increaseing the voltage by one cell can have a huge effect on the total power out.

Just remeber, if a motor says it's good for 900 watts, that means that you can load it to that much, don't expect it to pull 900 watts in every fan on any voltage.

For instance, if you buy a fan and motor that's been assembled, and it makes 1500 watts on 5S, if you drop it to 4S, it's not gonna make 1500 watts (less volts, less load). It will make more around 800 watts on 4S.




good start, just remember that electric is no more complicated than glow. It's not like you were born knowing how to tune your engines right?



maybe save that one for after you get a few good edf's flying, don't want to over complicate things.

Awesome post, Pete.
Smokescreen38 is offline Find More Posts by Smokescreen38
Reply With Quote
Old Feb 04, 2010, 07:50 AM
in way over my head
The Bambozler's Avatar
Memphis, TN
Joined Feb 2010
100 Posts
Thanks Pete. very informative. I am tring to find the 22 that will run well out of the box. SAPAC offers it in a dual motor, full flting surface ele's, and that is appealing. Will the SAPAC run well stock as I begin my training in this new model. Later is when upgrades/gyro's come in.
What is the quality of the ESC, motors and batteries servos supplied with the SEPAC? Is there room in the airframe for the mentioned upgrades I mention?
The Bambozler is offline Find More Posts by The Bambozler
Reply With Quote
Old Feb 04, 2010, 09:33 AM
DqP
Alert5 RC International
USA, FL, Fort Lauderdale
Joined Jul 2009
170 Posts
Great explanation Pete!

The F-22 airframe is open and its a foamie so you can make room if needed. The electronics included are pretty basic and do the job (especially if you are learning). Still i think changing the esc's out is definitely a must. I've changed out my elevator servos and nose gear (rudder) servos to 65HBs to give it a little bit more stability.
DqP is offline Find More Posts by DqP
Reply With Quote
Old Feb 04, 2010, 02:35 PM
in way over my head
The Bambozler's Avatar
Memphis, TN
Joined Feb 2010
100 Posts
BH f22??

I believe the f22 is the airframe.
SO the question now becomes what MFG. I plan to purchase one this weekend or early next week, and I am getting ancy. I want one VERY soon.

I went back to www.bananahobby.com and found their offering on this. It has a single fan, retracts, and, seemingly, a strong esc, battery and motor. I do want to get a TXRX that is 2.4 but I want a computer type. does the one that is in the RTF version do this? is it any good at all?

Does anyone have this plane?

Do the retracts have suspension?

SAPAC model is less $ but then I have to upgrade battery, and ESC, so I am hesitant.

Any advice?
Thanks.

Also, does anyone do a box review for either plane?
The Bambozler is offline Find More Posts by The Bambozler
Reply With Quote
Old Feb 04, 2010, 04:39 PM
DqP
Alert5 RC International
USA, FL, Fort Lauderdale
Joined Jul 2009
170 Posts
I would definitely get the SAPAC over the others. first, the airframe foam is much better. i have a bananahobby f-18(90mm) and even at that size the foam seems so much cheaper compared to the SAPAC. I have the hobby Lobby F-35 and love the plane but man, if you sneeze in the direction of plane, it think you could chip it.

on of my SAPAC F22s looks like frankenstein, glued together many times that i've broken the nose clean (or should i say jagged) off. Both the SAPAC F-16 and F-22 have outstanding foam airframes.

secondly, i dont like the fact that banana hobby's F-22 uses elevators instead of full stabs.

thirdly, you might want to check some threads about Bananahobby to see if their customer service has improved. i personally had a miserable experience with my order a couple of months ago and finally was able to cancel it to get a refund.
DqP is offline Find More Posts by DqP
Reply With Quote
Old Feb 04, 2010, 04:56 PM
in way over my head
The Bambozler's Avatar
Memphis, TN
Joined Feb 2010
100 Posts
DqP

Sweet vidio BTW. Was that SAPAC stock? Also, I plan to paint the Tiger meet style on mine, so how is the stock paint? Would I need to sand to foam, prime, then paint? Paint type suggestions? Poly, acrylic?...

What does DqP mean?

Thanks, I know I ask some rookie Q's.
The Bambozler is offline Find More Posts by The Bambozler
Reply With Quote
Old Feb 04, 2010, 05:09 PM
in way over my head
The Bambozler's Avatar
Memphis, TN
Joined Feb 2010
100 Posts
Quote:
secondly, i dont like the fact that banana hobby's F-22 uses elevators instead of full stabs.

Totally agree. The fixed gear version has independant servs. I was thinking of fixing the retracts for now, modifying the flight control servos until I could get better RxTx...

Hook me up, feed the knowledge. LiPo batteries: What do the specs mean? I understand volts and mAh, what is 20c etc? what is 1S= to? How fast can they be recharged? Balance charging means what exactly? Just think this is where I should start in understanding PWR system... Your input is highly regarded. Thanks.
The Bambozler is offline Find More Posts by The Bambozler
Reply With Quote
Old Feb 04, 2010, 06:20 PM
DqP
Alert5 RC International
USA, FL, Fort Lauderdale
Joined Jul 2009
170 Posts
I'm pretty new at this but here's a few things i understand. "S" is the number of cells to get the correct voltage. since each cell is about 3.7volts, a 3S would be about 11.1V, 4S = 14.8V, etc. so depending on how much you need to run your power plant.

I didn't want to butcher it up so here's the C explanation from the wiki:
"Cell capacities are rated in ampere hours (Ah) or milliampere hours (mAh). A 1000 mAh battery is the same as a 1 Ah battery: both will supply 1 A for 1 hour. The C rating commonly associated with lithium ion batteries refers to the maximum current supply capability as a multiple of the cell's capacity: for instance, a 1 Ah, 20C battery should be able to supply 20 A continuously without damage. A useful way to calculate how long a battery will last for under heavy load is to multiply the Ah capacity by 60 to give ampere-minutes, so a 1 Ah battery is a 60 ampere-minute battery; to calculate how many minutes the battery will last, just divide by the average current drawn (e.g. a 10 A average current draw will mean that a 60 ampere-minute battery will last for 60/10 = 6 minutes)."

It's really quite a balance but for me, i try to max out my flight times (instead of speed) i try to keep my RPM about 50,000 for my edfs for optimum flights. For this depending on what motor kv is i can choose my battery. RPMS = Motor Kv x Nominal Voltage. My stock motor F-22 has a 3820 Kv so it loves running a 4S (14.8v) -> 3820Kv * 14.8v = 56,536 RPMs, my upgrade F22 is a 4800Kv so i run it on a 3S (11.1v) = 53,280 RPM.

I typically charge my batteries (to maintain more life) around 2A. takes about an hour or so per and i have about 3 chargers.
DqP is offline Find More Posts by DqP
Reply With Quote
Old Feb 04, 2010, 07:23 PM
in way over my head
The Bambozler's Avatar
Memphis, TN
Joined Feb 2010
100 Posts


I think I get it. nice. Thanks. How about ESC choices? Do some offer features that others do not? I.E: battery is nearing end of charge so it goes into a lower output to the EDF, do they all have these features?

Why the heat shrink around the heat sink? seems like the sink loses surface area. I understand the esc deals with very high voltages/amps. so if it is an insulation thing, why not use RTV or hot glue on the circuit board for insulation???

Okay, SAPAC jet seems like the correct thing but will need some adjustment in the ESC area. If I can stay off the throttle too much to keep the AMPS down, will it be okay? If I increase the ESC, should I go to a different batt?

Why does SAPAC ship a model that is obviously needing removal of under adequate component? The motors and fans are good right? How are the servos? the ESC thing does not make since to me if it is under size...
I'ma go do more looking now, armed with some new know...

Thanks for the help.
The Bambozler is offline Find More Posts by The Bambozler
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion EDF F/A 18 vs. F-22 advice/MFG The Bambozler Foamies (Kits) 0 Feb 02, 2010 11:31 PM
Alert F-18 vs F-18 takeoff1 Fuel Plane Talk 0 Sep 13, 2009 09:00 PM
Custom built Depron jets. F-4, F4D, F-5, F14, F-15, F-18, F-22, and more, prop or EDF ram3500-rcu Product Announcements 37 Jan 22, 2009 01:36 PM
Discussion Deciding: Phase3 F-16 vs Sapac F-22 vs HL F-18 mike_perth Foamy EDFs 102 Sep 07, 2008 12:11 PM
Wanted F-15, 16, 18 or f-22 EDF MTXMUGEN Aircraft - Electric - Jets (FS/W) 2 Oct 10, 2007 10:14 PM