Darnell type 21 submarine, need some help

Hi, I purchased a Darnell model submarine off an auction site. The seller told me that it all worked, but on unpacking the model I found that it had been robbed of a lot of it running gear. The biggest problem I have is the air pump. The original pump I believe was very small from a steam model boat. But today I can’t find a small bi-directional air pump that will do the job, I have purchased around three pumps on line, only to find that they are one direction, or too big like the one in the picture, which will not allow space for a battery in the compartment. I don’t really want to rip it all out, so can anyone help with pointing me to a suitable air pump. Thanks

I think I know how you feel. Where do I go from here?!

https://www.theassociationofmodelsubmariners.com/t1092-darnell-type-xx1-graham-s-dad-s-boat-for-refurbishment

I found it very difficult to get the Darnell, as originally designed, to work. Technology moves on.

I don't have much experiences of pumping air but peristaltic pumps  can do what you want - rather slowly but they are easily reversible.

https://www.theassociationofmodelsubmariners.com/t1955-nautilus-ii-by-robert-fulton

Sorry I haven't been able to find a photo of the pump I used, but it is very like this one on eBay available for about £35:

https://www.ebay.co.uk/itm/266798195889?itmprp=cksum%3A266798195889a763709292bd48249e3de270920a674d%7Cenc%3AAQAJAAABkP9d%252BMZSXlztIfYFu3kI%252B7ft0VcQix7rTrUVdiJwc2upzwLfM%252B2UEqu0ZqdXqu2qWe6up6s9MSEY%252BWikIwEh4xLkizL%252BG%252Fyhg6cdW4xfkbb75erVQBYYISNxGN1au%252BE0eJ778JYYSAyLJRupNiZky3B2UHpMsaEp7JRgW9fuueOszPlG9eCPE4mSzJx4EejjZE0v1xx3s4HgKujjhEB3s6n28TmXJ5jEirKjJbd11dcK8XU8WGyDI%252Fsd%252BdkX264vp2vTw1B8jX4Pdb9Y0ndSY40sm0IqEHlMrOj2%252Fc4aWUPHXZoQISDdmxnmylyZqjxJGKXRJ20JRCy--Hy9gXhn8eD9JxXp0B7ZWrjx9mCn0iD6l2e3dkIwNUwLzPmnj6Pfi0Zcgadmxm397I7X%252FHIrfwxHMhrk3FohPG8CCdu4HdAd%252FdSF4hwqfgjoLDLHWGSly6Klc39ZGU4RgUE97kAoYpS1AE5XRMwik7WdBDFcTsVaoXoC68IPEg8eVjIcPQkv8LrA%252FeW6qMvrcPP8xldlXB0%253D%7Campid%3APL_CLK%7Cclp%3A4429486&itmmeta=01HYNH5V2MEP7W3S8ZAWGSTRGF

Generally most people pump water. It is easier to do and many pumps are available. I have used car screen wash pumps and have seen caravan water pumps also used.

These are the smallest peristaltic pumps I can find. They work, but they are very slow so I just use it for the trim tank now, but it can dive with it if you're not in a hurry.

https://www.aliexpress.com/item/1005005336619812.html

another option is to use a pair of diaphragm pumps with T connections so one is for sucking in and one for blowing out.

Thanks, I did find a pump that works. It's a bit slow but I believe it will do the job. I have found that the original pump was a brass steam driven piston pump for model boats. Something know longer made

If you read my build log (I gave you a reference in earlier post) you will see the original pump.
(They were not very good. Slow and they leaked and so pressurised the WTC.)

David

Hi, I did read your original post. Did you keep the original pump or update it?.

Hi Michaelc
I have a pump sitting on my desk, I also have the kidney bags that were used in the boats.
Fred