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Hangar 9 Sundowner 36 ARF for EF-1 Pylon Racing

Hangar 9's sleek new Sundowner 36 is now NMPRA approved for EF-1 racing. Mike McDougall takes one out for some Go Fast and Turn Left Fun.

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Introduction

Wingspan:51.5"
Total Wing Area:400 sq. in.
RTF Weight:3 lb. 9 oz.
Length:44"
Wing Loading:20.2 to 26 oz/sq. ft.
Transmitter:JR 9503 DSMX
Servos:(2) JR Sport MN48 & (2) JR DS388
Receiver:Spektrum AR7010 DSMX
Motor:E-flite Power 25 1250kV
Battery:Racing 4-cell 2500 or Sport 3-cell 3200
Prop:Racing 8x8E - Sport 10x7E
Racing Power:1050 Watts
Racing Power Loading:295 Watts/lb or 18.4 Watts/oz
Sport Power:600 Watts
Sport Power Loading:170 Watts/lb or 10.5 Watts/oz
Manufacturer:Hangar 9
Available From:Horizon Dealers and Fine RC Hobby Shops
Retail Price:$269.99
Street Price:$179.99

The Sundowner 36 is Hangar 9's latest addition to their very successful Sundowner Pylon Racing series. The 36 is the smallest in the series so far and has recently been certified by the National Miniature Pylon Racing Association for the new Electric Formula 1 Pylon Racing Class of competition. The Sundowner 36 features a fully sheeted built-up two-piece wing and the excellent parts fit and finish we have come to expect from Hangar 9. While it is slightly larger than its stable mate, the E-flite Pogo LR-1A, the Sundowner is more streamlined, and the higher aspect ratio wing makes it smoother around the pylons.

If you are wondering what all the hype is about with this EF-1 racing thing, then you should probably check out the RCGroups Thread on EF-1 Racing.

If you're feeling the "Need for Speed" or if you think you might want to try this new EF-1 class of racing, then the new Sundowner 36 is the perfect place to start. Let's put one together and see how she stacks up against the competition.

If you're not too sure about this racing thing, but you want to have the wildest sport/aerobatic plane at your club field, the Sundowner 36 may have some hidden surprises in store for you. Stick with me to the end of the review, and I'll show you how to turn this fire-breathing Reno-racing dragon into a pussycat.

Kit Contents

Kit Includes:

  • All Parts pre-covered in an attractive UltraCote color scheme
  • Hinge Slots precut and CA Hinges in place
  • Fully Sheeted Fuselage
  • 2-Piece Sheeted Wing with Carbon Spar and mounting tabs
  • Horizontal Stabilizer & Elevator
  • Vertical Stabilizer & Rudder
  • Fiberglass Motor Cowl & Wheel Pants
  • Streamline Canopy and Large Front Hatch
  • 2-piece engine mount, fuel tank, and generous hardware package
  • 48-page photo-illustrated assembly manual

Kit Requires:

  • .40 two-stroke glow engine, Power 32, or Power 25 Electric Motors
  • Minimum 4 channel radio with 2 Mini servos & 2 MG Micro servos
  • 2-6" servo extensions
  • RX switch harness
  • Thin & medium CA glue
  • 5-minute & 15-minute Epoxy glue
  • Thread locking compound
  • Assorted drills, knife blades, files, and hex wrenches

Recommended by Hangar 9 and supplied by Horizon for this review:

  • E-flite Power 25 -1250 kV Brushless Outrunner Motor
  • E-flite 60 Amp Brushless Speed Controller
  • E-flite 4-cell 2500 mah 30C Lipoly battery
  • Spektrum AR7010 receiver
  • 2-JR Sport MN48 Mini Servos
  • 2-JR DS388 Micro Servos

E-flite Power 25 Outrunner Motor
E-flite Power 25 Outrunner Motor
Type Brushless Outrunner
Continuous Current 50A
Max Surge Current 58A
Max Power(watts) 850W
RPM/V 1250 kV
Weight 183g
Number of cells Li-Po 3s-4s
Shaft diameter 5mm
Motor Connector 3.5mm
Price $69.99

E-flite 60-Amp Pro Brushless Controller
E-flite 60-Amp Pro Brushless Controller
Type Brushless Speed Controller
Max Cont. Current 60A
Max Surge Current 75A
Number of cells Li-Po 3-6, NiCD/NiMH 9-18
Battery Cut Off Preset or 70%
BEC 2.5 Amp Switch Mode
Weight 66 gm
Dimensions (L x W x D) 76 x 33 x 13mm
Power Connector EC3 Type
Bullet Connector 3.5mm
Price: $84.99

E-flite High-Power Battery
E-flite High-Power Battery
Batteries Type Lithium Polymer
Number of cells 4
Capacity 2500 mah
Voltage 14.8
Weight255 gm
Dimensions (L x W x D) 132 x 43.2 x 19.1mm
Maximum Continuous Discharge 30C
Maximum Continuous Current 75 amps
Main Power Leads 12 AWG
Power Connector EC3 Type
Price: $64.99

Spektrum AR7010 Receiver
Spektrum AR7010 Receiver
Frequency Band 2.4 GHz
Type DSMX Frequency-Agile
Number of Channels Seven
Receiver Type Dual RX
Antenna Two Antennas per RX
Range Class Full Range
Main RX Size 1.85" x 1.0" x .62"
Remote RX Size 0.98" x 0.89" x 0.27"
Weight 0.49 oz (14g)
Voltage Range 3.5V - 9.6V
Price $89.99

JR Sport MN48 Servo
JR Sport MN48 Servo
Type Analog
Size Factor Mini
Bearing Single Ball Bearing
Operating Speed 60į .18 sec @ 4.8V
Torque 48 oz-in @ 4.8V
Weight 22.7g/0.8oz
Dimensions 1.3" x 0.58"x 1.02"
Gear Type All Nylon
Price $23.99

JR DS388 Servo
JR DS388 Servo
Type Digital
Size Factor Micro
Bearing Dual Ball Bearing
Operating Speed 60į 0.16 sec @ 4.8V
Torque 60 oz-in @ 4.8V
Weight 20g/0.7oz
Dimensions 1.14" x 0.43"x 1.18"
Gear Type Metal
Price $69.99

Assembly

The 48-page Assembly Manual includes numerous pictures and helpful building tips. Seasoned ARF builders should have no problems with this plane, however some of the assemblies require a specific sequence of steps. The various parts should be inspected as they are unpacked and the UltraCote covering tightened as needed before construction begins.

Fuselage

Construction began with the Fuselage assembly. The horizontal stab and elevator were the first items on the build list followed by the vertical stab and the rudder. It was important to follow the sequence in the assembly manual to keep from missing an important step. The Sundowner ARF came with all of its flying surfaces hinged but the hinges were not glued in place. All of the hinges needed to be removed, a 1/16" wicking hole drilled in the center of each hinge slot location, the hinges reinstalled, and then thin CA glue applied to each one.

EF-1 Pilots have recently been lengthening their tail wheels or installing tall tail skids to raise the tails of their planes. They have claimed that the resulting lower angle of attack helped to reduce the effects of motor torque on takeoffs. I decided to install my tail wheel lower on the rudder to raise the tail and help the Sundowner sit flatter on the runway.

The canopy/hatch assembly fit was a bit fussy and required some fiddling to get it set in place. I rounded the front edges of the carbon pins and then I cut the top of the opening to provide additional clearance for the cowl mounting bolt and washer. These changes fixed the problem.

Landing gear were next on the list. Racers have found that proper landing gear placement in relation to CG was critical to insure straight takeoffs and to allow no-bounce landings. Many Pogo LR-1A pilots have turned their landing gear around to get the center of the wheels closer to the CG. I found that the stock gear location on the Sundowner worked very well and there was no need to turn them around.

The last part of this construction sequence involved the installation of the elevator and rudder servos and their control linkages. The pushrods were installed through the front of the fuselage and had to be installed before any of the motor or ESC leads were in place. Once again, I was glad I followed the assembly manual sequence instead of jumping ahead.

Wings

Wing assembly began with the hinging of the ailerons and then progressed to the installation of the servos and control linkages. The low-profile digital DS-388 servos came with some super-strength double-sided servo tape squares. I decided to omit the rear hardwood blocks on each servo and use the servo tape squares in their place. This process allowed me to center the servo output arm in the servo opening fore and aft as well as side to side. I cleaned each servo with alcohol, and I applied some thin CA to the servo cover wood to give the tape a clean smooth surface for adhesion. I found that the servo tape squares were very solid and probably would have worked all by themselves, but I installed one hardwood block to each servo as a backup for the tape, just in case.

Motor Installation

The E-flite Power 25 1250kV motor has been officially approved by NMPRA for the EF-1 event and has become the motor of choice for this event. Since E-flite made two versions of the Power 25 motor, I made sure I had the 1250kV NMPRA version for this Sundowner review. When I tried to mount the motor, I found that Hangar 9 had updated the spacer and bolt lengths for the Power 25 and that the manual still referred to the original shorter dimensions. The Power 25 motor used 30 mm (1-3/16") spacers and 45 mm (1-3/4") bolts to mount the motor to the firewall. Future versions of the Sundowner manual will reference these longer dimensions.

Before I mounted the motor, I solved the mystery of the undocumented triangle stock. I found a piece of triangle stock among the hardware packs, but I couldn't find where it belonged. If found that the left side of the rear of the firewall was missing its reinforcing triangle stock because some of the larger combinations of motor/engine mounting bolts would interfere with the stock if it were installed. Since the Power 25 mounting bolts did not interfere, I epoxied the stock in place.

Radio Installation

The assembly manual showed a very good radio installation and a workable location for the main receiver and the remote receiver. However, I mounted the main receiver sideways and the remote receiver vertically behind the servos. This was just a matter of personal preference to get the remote receiver antennas further away from the battery and the ESC. No matter how you decide to mount your receivers, remember that the factory recommended installation places the main receiver and the remote receiver antennas at 90 degrees to each other.

Motor, Battery, & ESC Cooling

There are some of EF-1 builders that restrict cooling airflow to the very minimum to help reduce airframe drag. They have had excellent results using the optional 2" Aluminum Spinner to help transfer motor heat away from the windings. However, I believe that when it comes to cooling, MORE is better! Over the years I have found that proper cooling extended motor life and improved ESC performance. The best way I have found to cool a brushless motor is to provide direct airflow through the motor and over the coil windings. One way to provide direct airflow is to force the air through the front of the spinner, through the spinner back plate and then through the motor. This cooling method doesn't require any additional holes in the cheek cowls or any additional internal ductwork to redirect airflow. The Sundowner cowl came with a hole in the lower portion to direct cooling airflow straight to the ESC. The only thing missing from the fuselage was a place for all that cooling airflow to exit the framework. I decided to cut two holes in the bottom of the fuselage just behind the wing. I used the scientific TLAR method for sizing the holes. TLAR=That Looks About Right

Completion

The completed Sundowner weighed only 3 pounds and 9 ounces ready to race! I was very surprised. The finished Sundowner weighed almost 1/2# less than the lightest advertized kit weight and only 3 oz. more than my Pogo. The Sundowner was only 6 oz. over the minimum weight allowed for the EF-1 class of racers!

To achieve the proper CG, I mounted the 4-cell E-flite battery all the way forward against the back of the firewall.

I set all the surface throws at the recommended amounts and, since I prefer to fly with exponential, I added 25% exponential to the low rates and 35% exponential to the high rates.

Flying

Basics

Pylon racing airplanes fly very fast and may be hard to keep up with sometimes. However, the Sundowner 36 was different. It was one of the easiest flying EF-1 racers I have flown to date. I think the extra wing area and the higher aspect ratio made the Sundowner smoother around the pylons. The only way to fly a good pylon course is to Practice, Practice, Practice, and the Sundowner 36 lets you get that practice at a more relaxed pace with an 8x6E prop.

Switch to a 3-cell battery pack and a 10x7E prop and the Sundowner 36 becomes a great sport/aerobatic plane.

Taking Off and Landing

The bane of pylon racing is the takeoff. High-powered motors and full RPM takeoffs can produce some nasty torque effects. Luckily the Sundowner doesn't exhibit near as much takeoff torque effect as its sibling the Pogo. I found that I only needed a touch of right rudder on most of my takeoffs.

Landings took a little practice. The Sundowner 36 is a slick airframe and with the 8x8E prop it doesn't slow down very easily so I had to cut power on the downwind leg and go out further than with my sport planes before I turned on final. The Sundowner can be slowed down a little with the elevator for a 3-point landing, or wheel landed and allowed to coast to a stop if your runway is long enough.

In sport plane configuration with the 10x7E prop, the Sundowner 36 slowed down much quicker and settled easily into a nice steady 3-point landing stance. It still took a longer landing approach than a Pulse 40, but it was very manageable.

Racing

The Sundowner 36 was designed to race and it performed that task very well. I found the Sundowner flew steadier on the course and seemed quicker around the pylons than its sibling the Pogo. The Sundowner held its heading very well as it rolled into and out of pylon #1. It was very stable and easily controlled on the straightaways. Minor course adjustments resulted in smooth flight path changes. This was one sweet flying pylon racer!

Sport Aerobatics

With only a couple of minor changes, the Sundowner 36 became a very respectable sport plane. The E-flite Power 25 on a 3-cell Lipo pack and a 10x7E prop had plenty of power for those big loops and long vertical lines. Stall turns, rolls, and snaps were a thing of beauty and inverted flight was rock solid even at low speeds. Knife edge had just a little coupling, but looked so nice.

Is This For a Beginner?

No. Pylon Racing planes are not suitable for first-time pilots. However, the Sundowner is very well suited for first-time Pylon Racers. The extra wing area and the high aspect ratio wing platform make the Sundowner very mild mannered all the way around the course. Pilots with intermediate flying skills and a little taildragger experience should have no problems. First time racers should start out with the APC 8x6E on 4-cells or the APC 10x7E on 3-cells for their practice sessions until they get a good feel for the plane.

Flight Photo Gallery

Racing Video Gallery

How hard could it be to shoot some video of a small 100+ MPH airplane flying 20 feet off the ground?

Let's see......

Downloads

Aerobatic Video Gallery

Now that the video camera is all warmed up and the videographer is settled down a little, let's see how the Sundowner 36 flies as a sport/aerobatic plane with a 3-cell battery pack and a 10x7E prop.

Downloads

Conclusion

The Hangar 9 Sundowner 36 is a great entry level EF-1 Pylon racer that flies so well it can put you in the winnerís circle on any given race day. For the other 40+ weekends of the year when you are not racing, the Sundowner 36 can be flown as an aerobatic sport plane that looks like itís going 100+ MPH even when its sitting still.

So whether it's hard core EF-1 racing, or showing off with a few pattern moves at your club field, the Sundowner 36 is just what the doctor ordered. Trust me, my son's a Doctor.

Pluses:

  • Great Looking Racer
  • Quick and Easy Build
  • Very High Quality ARF
  • Well finished Fiberglass Parts
  • Great Flying Pylon Racer
  • Great Flying Sport/Aerobatic Plane

Minuses:

  • Lack of Precut Cooling Air Exits
  • Motor Spacer/Bolt Dimension Error
Last edited by Angela H; Aug 09, 2011 at 02:43 PM..

Discussion

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Old Aug 09, 2011, 03:58 PM
We shall serve the Lord
kingsflyer's Avatar
United States, TX, Kingsland
Joined Sep 2005
4,825 Posts
I've been flying the Sundowner 36 for over four months now and I'm still lovin' it! I haven't entered a single race yet, but I've been Sport flying it almost every week. The SD36 still gets lots of favorable comments every time I take it to the field.

New motor recently approved for EF-1 use.
OS Brushless Motor OSMG9525, 1200 Kv motor. Product number: OMA-3820-1200
http://www.osengines.com/motors/

Here's my update after six months --- I have recently been Sport flying the Sundowner 36 with a 10x5E prop and the 4-cell battery packs I use for practice racing. This setup is awesome! It is not as fast as the racing setup with the 8x8E, it draws fewer amps so it can fly longer, it still has unlimited vertical, and it slows down better for landings. I like this Sport setup even better than the 3-cell & 10x7E Sport setup I flew for the review.

McD
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Old Aug 09, 2011, 07:40 PM
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JustPlaneChris's Avatar
Austin, TX
Joined Sep 2005
11,418 Posts
Mike that's a great looking plane and an excellent review! I've been looking at these EF-1 planes ever since I saw George Parks fly his at the ARCA field here in Austin. They look like fantastic fun.

I have to ask a question though... that field in the video looks really familiar. That wouldn't be the RC field in Kingsland, TX would it? If so, I was invited up there by Kenny Sierra to fly once and had a very enjoyable visit.
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Old Aug 09, 2011, 09:35 PM
We shall serve the Lord
kingsflyer's Avatar
United States, TX, Kingsland
Joined Sep 2005
4,825 Posts
I was honored to fly against George and Fred French at your club event earlier this year. Me and my Pogo finished right in the middle of the field of 14 entrants. I had a great time and learned a lot about EF-1 racing.

If you think you might be interested in EF-1 racing, the Sundowner 36 would be a great choice because you can race it one weekend and you can change the prop and battery and sport fly it the next.

You guessed right, the field is in Kingsland and is the home of Highland Lakes Flyers, Inc.
http://www.highlandlakesflyers.org/
You need to come on back over and fly with us a little more.

Mike McD
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Old Aug 10, 2011, 07:11 AM
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Canada, SK, Saskatoon
Joined Jan 2011
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Nice review MIke, Great job!
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Old Aug 10, 2011, 07:42 AM
atlav8r's Avatar
Cumming Ga
Joined Apr 2002
2,865 Posts
Good job Mike and it looks like a lot of fun. Wonder if the Power 32 would be a better choice?
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Old Aug 10, 2011, 07:51 AM
We shall serve the Lord
kingsflyer's Avatar
United States, TX, Kingsland
Joined Sep 2005
4,825 Posts
For EF-1 racing, the motor, prop, and battery are all specified in the rules. For sport flying or all-out speed runs, the sky's the limit -- or maybe the strength of the balsa and plywood is the limit.

The Sundowner 36 is set up to take the Power 32, but I wonder if the increased weight of the motor and extra Lipo cells would be worth the effort. The lower kV of the 32 would require a larger prop or more cells than the 1250 kV Power 25. I think you could get an 11" prop to work OK with the stock ground clearance so that shouldn't be a problem. I guess we will just have to wait till some users begin to explore the "outer limits" of the airframe's capabilities to see if the 32 would actually be better.

McD
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Old Aug 10, 2011, 03:25 PM
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USA, TX, Trophy Club
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Do your hands shake a little after the flight? Great stuff Mike!
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Old Aug 10, 2011, 04:52 PM
We shall serve the Lord
kingsflyer's Avatar
United States, TX, Kingsland
Joined Sep 2005
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Quote:
Originally Posted by pda4you View Post
Do your hands shake a little after the flight?
Not as much as with the Pogo! The Sundowner 36 is now my windy weather Go-To airplane. Its so much fun to sport fly that I don't care if I ever race it -- but I know I will .

McD
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Old Aug 10, 2011, 08:44 PM
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sw michigan
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Could you put an os 46 in it?
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Old Aug 11, 2011, 10:10 AM
We shall serve the Lord
kingsflyer's Avatar
United States, TX, Kingsland
Joined Sep 2005
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I don't know if that that would be such a good idea. A 46 would probably be pretty heavy for this plane. You would have to add a lot of tail weight to offset the engine weight and you only have 400 sq. in. of wing area so your wing loading would end up to be pretty high. That being said, a light weight racing 40 or 46 engine might be fun for a little while. Back in the day, we would take smaller planes and put racing 40s in them and launch them by holding them pointed straight up and just letting to. However, even with extra reinforcement, and throttle restraint, the airframes would eventually fail due to the high wing loadings.

McD
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Old Aug 11, 2011, 10:20 AM
DHG
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United States, CO, Arvada
Joined Jul 2010
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Quote:
Originally Posted by kingsflyer View Post
If you think you might be interested in EF-1 racing, the Sundowner 36 would be a great choice because you can race it one weekend and you can change the prop and battery and sport fly it the next.

Mike McD
Mike,

I don't mean to quibble, but the same can be said of any of the EF-1s. I flew my Pogo with a 3S pack (no other changes at all) and it was a terrific, gentle, aerobatic sport plane. Top speed was reduced, of course, but it was still a ball to fly.

Cheers,

Duane
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Old Aug 11, 2011, 10:35 AM
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United States, TX, Kingsland
Joined Sep 2005
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You are 100% correct. The Pogo on 3-cells also makes a great sport plane, but the Sundowner with it's extra wing area is a little easier to fly than the Pogo. I never meant to imply that the Pogo or any of the other EF-1 planes were not great planes to race AND sport fly, I just think the Sundowner is easier to fly.

McD
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Old Aug 11, 2011, 10:58 AM
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USA, KS, Derby
Joined Mar 2003
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Mike,
Did you just cut that hole on top of the white plastic spinner or did it come that way?

Also, how does the plane handle a slow landing approach when there is no head wind.

Thanks,
Rico.
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Old Aug 11, 2011, 01:03 PM
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United States, TX, Kingsland
Joined Sep 2005
4,825 Posts
The spinner did not come with the hole. I used a Dremel cutoff wheel and sliced off about 1/4" off the front of the spinner and used a 1/2" sanding drum to smooth up the rough edges. I then used the Sundowner motor to spin the propeller-less spinner and used the sanding drum and some sheet sandpaper to finish up the opening.

The landing speed of the Sundowner is slower than most Warbirds but it's higher than a normal sport model because of it's slippery pylon racer design and relatively thin wing airfoil. That said, it can be slowed down and landed in a three-point stance, you just can't drag it in nose high like you can a thick wing plane like a Twist.

McD
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