[7pilot]

I have a set of the Johannsen tanks that have yet to be installed. Since I fly a lot of cross country I was pretty happy they were included in my kit when I purchased it from the original builder. Now I am starting to have a lot of questions. Since they were originally sold on the Van's web site, I am assuming that there was some testing of them? Or at least a satisfactory evaluation that they would not greatly impact the flying characteristics and that the wings can handle the weight? I am not talking about doing aerobaticts with fuel in the tips, and I am not talking about changing my GW to compensate for the additional fuel....so please don't flame me.

For those that have the Johannsen tips installed and flying, can you tell about your experiences flying with them? Are #6 screws and nutplates really enough to support another 50+ pounds in addition to the weight of the wing tip tank itself?

I can't typically fly longer than just the main tanks comfortably, but the additional fuel does give you a bit more flexability to elect not to refuel at a bathroom stop in favor of getting to significantly cheaper fuel.

One more question... I was able to find an article on the WH fuel tanks in RVator, has there been one on the Johannsen tanks? Anywhere?

Thanks!

Stewart

 

[vic syracuse]

Hi Stewart. I built my RV-6 with these tip tanks, and they performed wonderfully. I did do mild aerobatics without fuel. I installed them with the #6 screws and nutplates and never had any problem with them. It was really nice to be able to add the extra fuel for longer trips.
Vic

 

[Captain Avgas]

Tip tanks no longer sold.

I have a set of the Johannsen tanks that have yet to be installed. Since I fly a lot of cross country I was pretty happy they were included in my kit when I purchased it from the original builder. Now I am starting to have a lot of questions. Since they were originally sold on the Van's web site, I am assuming that there was some testing of them?
Stewart

Vans definitely never tested the Johanson tip tanks and no longer sells them. Nor does Jon Johanson for that matter. A suspicious person might read something into that.

 

[moodyjr]

Tip Tanks

I have the Johanson tip tanks on my RV-8A but am still about 6 months from flying. I have used #8 screws rather than #6 - just personal preference.
If you have concerns I suggest you replace the #6 nutplates with #8's or add additional #6 screws between the existing screws.

I spoke to a few users here before buying the tanks - they were uniformly positive about the advantages of additional capacity with no adverse comment about handling.

FWIW here are some comments from Ray Jarvis (who I believe flies for Cathay) in response to similar questions.


"I have a set of Jon's new design tanks on my RV 8. They are the
new tip design and each holds 48 litres of Avgas, this is 16 litres per tank more than old design tips. My cruise burn is better than 31 Lt/Hr average and on a recent trip from Adelaide to Sydney to check it out I refuelled on arrival. For a 3Hr 10 min flight at 9,500ft, I replenished the tips only.
In Aust my A/C is approved for MTOW plus tip fuel, this concession
may vary from PFA. Aerobatics are prohibited with tip fuel. There are no appreciable adverse aerodynamic effects with fuel onboard, however it is noticeable when taxiing in gusting conditions, as the aircraft tends to "waddle" a little. Once airborne, no discernable difference in handling.
There are many advantages and I now have capacity for 252 litres
giving me over 8 hours 10 mins endurance and it would be possible for me fly Australia- New Zealand direct. Another advantage to range is the ability to multistage fuel and alleviates the need to buy expensive fuel as well as the capacity to uplift an entire drum if that is necessary, no wastage.
> regards
> ray jarvis."

I suggest that the most likely reasons for Jon no longer supplying the tanks are 1) their high cost 2) small market 3) cost of shipping to the USA & Europe
rather than any more sinister reasons.

John Moody
#82025
Melbourne

 

[Barry]

I have had Jons Johanson's tip tanks installed on my 6A for over 4 years now and I regularly use them. I like the possibility of being able to choose where I buy gas and also have the range to do long flights or out and returns without buying fuel.

I did not like the way Jon recommended connecting the tip tanks directly into the main tanks as there is the possibility of leakage through the main tank filler cap which is lower than the tip tanks. Also there is the possibility of the vent air pressure in the main tanks being higher than the vent pressure in the tip tanks which will stop all the tip tanks emptying completely.

I plumbed my tanks in so each tank can be selected separately. I also have the possibility of running on both tip tanks at the same time. However I have found from experience that one of the tip tanks empties faster than the other. This is perhaps due to the vent air pressure not being equal.

I know that Vans and perhaps Jon no longer supply there tanks however it is not a big job for somone with fiberglass experience to convert a set of standard fiberglass wing tips into tip tanks.

Barry