Shop our Airplanes Products Drone Products Sales

Hobbyking Avios Grand Tundra - RCGroups Review

The Grand Tundra is a high-wing taildragger centered around two massive tundra tires and a pair of shock absorbing landing gear. It's an rc bush pilot's dream and has successfully re-ignited the aviation spark in my life.

Splash

A Grand Bush Plane

Product:Avios Grand Tundra
Retail price:$349.87
Wingspan:67" (1700mm)
Length:49.6" (1260mm)
Material:EPO foam
LED Lights:Switchable landing lights, always on nav lights
Motor:Turnigy Aerodrive SK3 5045 500kV
ESC:60a Aerostar w/ Reverse
Included Propellers:17x8, 16x8
Recommended battery:4s - 6s 4000mAh
Battery used:4s 5000mAh
Recommended radio channels:7 channels
Available from:Hobbyking

The bush plane is a popular aircraft in the rc world, as it's the natural progression for a modeler is to add giant tundra tires to at least one airplane in their hangar, and then attempt to fly it off of the most inhospitable surfaces. The new Grand Tundra from Avios takes the guesswork out of sourcing sprung gear and truly soft tundra tires by pairing them with a STOL airframe, a giant propeller, and installed electronics. The resulting combo is a rugged high-wing that, in my case has inspired me to get back out and fly, even with the local temperatures barely above freezing.

In this review, I'll assemble the Grand Tundra and fly it at a relatively rough field with pilot CJ Kurella on the sticks. Let's get started.

What's in the Box - Fit and Finish

The Grand Tundra shipped to my door safely in a stout cardboard box and foam cradle, which is standard procedure for ARF foam aircraft these days. All parts were wrapped to prevent contact damage, and the only broken parts were a few of the vortex generators that were missing fins. Luckily, extras were included and I only had to use one broken one on the aircraft.

The airframe has a high level of completion from the factory. Servos are installed with the horns in the correct location, and all electronics were mounted and ready for service. The graphics were applied well with no issues worth noting.

One area that caught my attention was the plug-in connectors on the wing root. These types of connectors have been given a bad reputation in the past, and personally I think that reputation is completely unfounded. Some critics consider them a failure point, but I have never experienced an issue. The Grand Tundra's wing plugs slide together smoothly and show no signs of ever failing. Time will tell, but I'm confident in this design.

On this list of included electronics is a Turnigy Aerodrive SK3 5045 500kV motor, an Aerostar 60a ESC that's reversible for precise maneuvering on the optional floats, an LED lighting system with on/blink/off control for the landing lights, and an LED blinking beacon on the belly. Mini metal-geared servos are used for the control surfaces, and micro 9g servos are utilized for the flaps.

The landing gear and tundra tires are a work of art on the Grand Tundra. The main gear are made of steel and are quite functional with the included rubber bands absorbing the energy from even the hardest landings. Coupled with the very soft foam rubber tires, the Grand Tundra can taxi, takeoff, and land on very rough terrain.

Assembly

The photos below with captions detail the main assembly steps. As I say in every review, follow your assembly manual for detailed instructions. The Grand Tundra goes together very quickly, and even includes a Philips head screwdriver and hex head wrench for bolting on the main landing gear, the tail gear, and the elevator halves. The rudder snaps in without any fasteners.

The use of CA adhesive is required only for the vortex generators; place a small drop of foam-safe CA on the slit in the foam and press each vortex generator into place.

The shock-absorbing landing gear are a functional thing of beauty, and arguably the focal point of the aircraft... oh and those big tundra tires!

I was happy to discover that all servo horns were installed from the factory at their correct positions, and only minor adjustments to the control rod lengths were in order.

Transmitter Setup and CG

With my brand new Futaba 16SZ being used for control, I setup the Grand Tundra with the flap-to-elevator mixing, a necessary mix to prevent ballooning when the large flaps are deployed at high angles. A few degrees of down elevator with the flaps corrects any nose-up tendencies. Depending on the size of battery you use and your CG location, you may need to fine tune the amount of elevator you mix with the flaps. Next, I put the landing lights on a switch and plugged them into my receiver. The pair of landing lights on the wings gets 5v power from the receiver, and with a 3-position switch, can be cycled off, on, and flashing.

Aileron travel (end point adjustment) was set at 60%, elevator was set at 70% down and 110% up, and rudder was set at 100%. Expo was set at 45% for all control surfaces, making the Grand Tundra perform scale maneuvers nicely around center stick, but still allowing a nice roll rate when the ailerons were pushed hard.

The Avios Grand Tundra calls for a 4s to 6s 4000mAh LiPo, and I opted for what I had on hand: a 4s 5000mAh. She balanced easily with this 14.8v pack at the recommended 60mm back from the leading edge.

Videos:

Hobbyking Avios Grand Tundra - RCGroups Review Part 1 (5 min 54 sec)

Hobbyking Avios Grand Tundra Flight Demo - RCGroups Review Part 2 (4 min 36 sec)

Flight Report

As the name suggests, the Grand Tundra is a large airplane when compared to its little brother, the Durafly Tundra. But even with a 4s 5000mAh LiPo feeding power to the 500kv motor, the Grand Tundra feels light and nimble on the sticks. We flew the GT at a relatively rough field to test out the functional landing gear and soft foam tundra tires. I had my friend and test pilot CJ Kurella on the sticks as I shot photos and video.

From takeoff to landing, and every second of flight in between, the Grand Tundra flew on a rail and exhibited no bad tendencies.

With flaps down or up, the Grand Tundra gets on the wing and takes off quickly and easily. Rolling takeoffs are in the 15 foot range without flaps; cut that in half with the flaps at 45-degrees.

The big 17x8" prop pulls the GT around with authority, and acts as a massive air brake when at idle; you can hear it cutting through the clean air very noticeably.

General sport aerobatics weren't a problem for this oversized bush plane, although knife-edge flight required more rudder input than we had setup. Loops, rolls, and hammerheads were uneventful and quite entertaining... this isn't a sport aerobatic airframe but performed the maneuvers well.

As I said earlier, the oversized tires and sprung landing gear are the focal point of the Grand Tundra, and watching them do their job of soaking up the rough stuff was quite satisfying to watch. We flew a number of landings where we purposefully flared a foot or two off the ground, only to have the gear and tires soak up the impact without any issues.

The 4s 5000mAh LiPo provided flight times in the 8-10 minute range with 30% left over. That included a mix of sport aerobatics and flaps-down cruising. You could stretch 12 minutes out of it with some throttle management.

Conclusion

The Avios Grand Tundra has rekindled my love of flying model airplanes. Over the years, you begin to expect more out of airframes, and the desire for something new and unique becomes a daily reality. The Grand Tundra delivers on that with its off-road style landing gear and tires that just beg for take offs and landing in places other models wouldn't even consider rolling. The GT flies with authority at fast and slow speeds, making it an easy transition from a beginner high-wing airplane. Finally, it's a very complete ARF, meaning all electronics are installed and minimal assembly is required to get the Grand Tundra on the wing.

So if you're in the market for an airplane that will impress you and your flying companions, not only for its utilitarian looks but also for it's rugged and solid performance, then look closely at the new Avios Grand Tundra, as it will not disappoint.

RCGroups.com Review Policies

Our intent is to provide fair and unbiased reviews so that consumers can make informed decisions regarding new products. Some things you should know about our review process:

  • RCGroups.com review items are provided by hobby manufacturers and suppliers, some of whom may be RCGroups advertisers.
  • Review products are sent directly to independent reviewers, chosen by RCGroups.com.
  • RCGroups.com reviewers are not compensated by either RCGroups.com or the reviewed item's supplier. However, they are allowed to keep the review items at no charge.
  • Published reviews reflect the opinion of the author.
  • When a conflict arises between a review sponsor and a reviewer (which is rare), RCGroups attempts to work out a satisfactory solution for all parties. In some cases, this may mean that a finished review will go unpublished, or be subjected to editing for technical accuracy.
  • RCGroups reserves the final say as to whether an article is fit for publication.

It is always our intent to provide a place for honest and open commentary, and to put the needs of our visitors first. If you feel that something we've published is inaccurate, please let us know using the contact form.

Last edited by Matt Gunn; Mar 20, 2018 at 02:37 PM..
Thread Tools
Mar 20, 2018, 02:13 PM
Journalist
Rorschach 1's Avatar
Nice review with lots of photos. I have a few questions. Are the vortex generators optional? What effect if they are left off?
Rubber bands? Could you use springs instead?
Mar 20, 2018, 02:13 PM
RCG Admin
Jason Cole's Avatar
Killer!
Mar 20, 2018, 02:18 PM
RCGroups Editor
Matt Gunn's Avatar
Quote:
Originally Posted by Rorschach 1
Nice review with lots of photos. I have a few questions. Are the vortex generators optional? What effect if they are left off?
Rubber bands? Could you use springs instead?
They should be installed as they do assist with slow speed maneuverability, and any condition where the angle of attack is high. If you leave them off, there will be little slits in the wings visible.

I would stick with the rubber bands because the gear hooks are designed for them. Could you use steel springs? Probably. If the natural rubber look bothers you, you could use black rubber bands...
Mar 20, 2018, 02:22 PM
Journalist
Rorschach 1's Avatar
Quote:
Originally Posted by Matt Gunn
They should be installed as they do assist with slow speed maneuverability, and any condition where the angle of attack is high. If you leave them off, there will be little slits in the wings visible.

I would stick with the rubber bands because the gear hooks are designed for them. Could you use steel springs? Probably. If the natural rubber look bothers you, you could use black rubber bands...
Great idea
Mar 20, 2018, 02:27 PM
RCGroups Editor
Matt Gunn's Avatar
Quote:
Originally Posted by Rorschach 1
Great idea
If you order the Blue/Silver Grand Tundra, it comes with black rubber bands.


edit: Oops! I'm wrong. I saw a pre-production model with black rubber bands, but it looks like they have been replaced with natural rubber.
Mar 20, 2018, 04:22 PM
→ aRCee Moloko [YT]
Justapoke's Avatar
Nice review, great photos!

Make sure to do an amp check on 6S!
Mar 20, 2018, 04:29 PM
Admin Deluxe
Jim T. Graham's Avatar
We will be grilling Matt about all the aspects of this plane on our Thursday Youtube Live Hangout!!
Mar 20, 2018, 04:34 PM
Registered User
FoxProGT's Avatar
Nice review.
Mar 20, 2018, 04:45 PM
→ aRCee Moloko [YT]
Justapoke's Avatar

Serious Earobatics


Check out the flight video from Tom de Weerdt from the Netherlands for some VERY cool and serious earobatics / 3D / flying with the Grand Tundra:

Avios Grand Tundra - Review (10 min 35 sec)
Mar 20, 2018, 05:10 PM
Head NEAT geek
Tom Hunt's Avatar
The pre-production model Stuart sent me used O-rings instead of rubber bands. You could always sub them out for an appropriate size if you have access to them. I do like the rubber bands though as you can adjust the tension a bit by the number of wraps.

Nice review Matt!
Mar 20, 2018, 06:36 PM
Registered User
jimq26's Avatar
Yes, an excellent review for sure. I can hardly wait for mine to arrive. In the meantime I shall pass the flying time with its little brother, the original Tundra.

Anytime I have that number of servos along with switching for lights etc. I like to add a separate BEC (did as well on my original Tundra) so the ESC runs nice and cool.
Mar 20, 2018, 06:49 PM
→ aRCee Moloko [YT]
Justapoke's Avatar
Quote:
Originally Posted by jimq26
Yes, an excellent review for sure. I can hardly wait for mine to arrive. In the meantime I shall pass the flying time with its little brother, the original Tundra.

Anytime I have that number of servos along with switching for lights etc. I like to add a separate BEC (did as well on my original Tundra) so the ESC runs nice and cool.
Be aware that in a static test a few days ago the GT was pulling 78A I believe on 6S with the white prop. Either prop down (15x8) or replace the ESC with the 80A version if you plan to fly it hard on 6S.

Adding a BEC is always a good idea, but with these high amp numbers you might very easy fry the ESC.
Mar 20, 2018, 07:16 PM
Registered User
Quote:
Originally Posted by Justapoke
Check out the flight video from Tom de Weerdt from the Netherlands for some VERY cool and serious earobatics / 3D / flying with the Grand Tundra:

https://www.youtube.com/watch?v=PxFHE7Fe-Pc
If you give it small throws it propably won’t do some of the stuff I did with it.
I’m going to use it to teach a friend in the summer and will defo make a copy of the model in my tx and dial those down a bit.

That being said, I think you might want big(ger) throws and use some expo (or set up rates), that way you have more resolution which is nice in slow flight, while still being able to make tiny corrections in slow flight as well.
But then when you open up the throttle, you’ll have a lot more options and inherent potential fun
The opening shot is a 4s half throttle knife edge (sorry for the spoiler), so I don’t really understand the comment about knife edge in the review...

With the 1300mm a knife edge loop is a battle of character between the plane and yourself, with the GT it’s a lot more comfortable.

The flight envelope is really a lot wider than you would think...
Mar 20, 2018, 07:40 PM
RCGroups Editor
Matt Gunn's Avatar
Quote:
Originally Posted by Tomsky
The opening shot is a 4s half throttle knife edge (sorry for the spoiler), so I donít really understand the comment about knife edge in the review...
I think I explained it well. The plane would not hold a knife edge with the 100% rudder throws we used. It would just start to sink. With more rudder deflection it holds fine.


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Avios Grand Tundra from HobbyKing - Official Owners Thread. AndyHK Electric Plane Talk 2335 Today 01:14 AM
Review HobbyKing Avios RCGroups Extra 330LX Review Jason Cole 3D Foamies 288 Aug 10, 2018 08:44 AM
Review Avios Zazzy From Hobbyking - RCGroups Review Mean Joe Vermillion Electric Plane Talk 7 Apr 16, 2018 04:01 PM
New Product Avios Grand Tundra from HobbyKing AndyHK Electric Plane Talk 1703 Mar 14, 2018 05:14 AM